It's only fitting that on the first full-force day of the 2005 Bonnaroo Music Festival - the closest thing we have on U.S. soil to England's notoriously rain-soaked multiday music celebrations like the Glastonbury and Reading festivals - it's already a mud bath. An intermittent sprinkle throughout the day on Friday was enough to turn much of this 700-acre farm in Manchester, Tennessee, into a murky, waterlogged mess. And believe me this: From my vantage point on the cozy, sink-into-me-and-forever-hold-your-peace couch that I find myself lounging on in the mock living room inside the very dry Artist Hospitality Tent, it sure doesn't look like much fun.

The weatherman is predicting nearly five inches of rain (and a few tornadoes) by weekend's end, mostly thanks to Tropical Storm Arlene, which is bearing down on Mobile, Alabama, some 425 miles to the south. That means most of the festival's 80,000 concertgoers will spend a good portion of this four-day weekend soaked and miserable, while those with the right access passes (guests, artists, journalists, and a wealth of additional - and often questionable - VIPs) will be enjoying an entirely different festival - warm, dry, and happy as pie.

IF YOU'VE EVER attended a concert or are a fan of music, there's little doubt you have, at some point, wondered what goes on backstage. So, here's what you should know - there's much more to backstage than you might think (and we know what you might think). There are, of course, the usual suspects (bands and their entourages partying it up, production crews scrambling to make sure Dave Matthews doesn't trip on his way to the stage, PR people making sure journalists don't see anything festival organizers might not want the world at large to know about), but there are also unsuspecting surprises like adorable girls from Lee Jeans handing out free denims, and batting cages courtesy of Major League Baseball. If music festivals of this magnitude functioned as self-contained cities - let's say Omaha - then the backstage area would be a parallel universe more akin to Las Vegas.

"As a punter [regular Joe], I've been to Glastonbury, and I really enjoyed it," says Frames singer Glen Hansard, whose band of Irish lads spit out a blistering set of emotive rock in the That Tent (for the record, there's also the What Stage, Which Stage, This Tent, and the Other Tent) on Saturday. "But I must say, it's very different to have a pass, because you can go to a proper toilet; you can go to the artist's bar. Basically, when you're a punter, you spend your whole day queuing. You queue to use the bathroom, you're on a queue to drink, and you're on a queue to eat. Depending on how big the band is, you're even on a queue to see them."

Having covered music and entertainment for nearly 10 years, I've seen my share of backstage and hospitality areas. I watched Rage Against the Machine sonically pulverize the masses from the stage at Woodstock '97. I've eaten lunch across a cafeteria-style table from Blur/Gorillaz singer Damon Albarn and watched in curious wonder as Korn's Jonathan Davis paraded his toddler around a backstage area in New York on a leash. Really, I've seen it all. But nowhere have I seen things like King of Leon's Caleb Followill stepping up to the plate in a life-size batting cage or one of the members of Modest Mouse enraptured by a complimentary massage - both of which I happened to see at Bonnaroo '05.

IN JUST FIVE SHORT YEARS, Bonnaroo (a Creole word for "good times") has established itself as one of the very few landmark, mainstream-music destination festivals in the nation (only California's Coachella Valley Music Festival comes close in status or popularity). It has done so by specializing in what it calls grassroots music, known to everybody else as "jam bands." Although defining exactly what a jam band is can be quite difficult - the musicians involved often joke about not knowing what the heck it is - suffice it to say that there are several factors that are usually present.

If you can stretch a four-minute album track into a self-indulgent, 35-minute rock ramble every time you grace a stage, you are a jam band. Because of this, your fans are knee-deep in trading MP3s of your live gigs, which, of course, you encouraged the bootlegging of in the first place (yet another factor). Last, but not least, your fans put up with said rock operas because many of them not only love music but also might love other unmentionables that we don't print in family publications such as this. Wikipedia, the online dictionary, sums it up as such: "Although usually associated with psychedelic rock, jam bands often draw on various musical traditions, including funk, progressive bluegrass, blues, country music, rock and progressive rock, folk music, and jazz. Jam bands sometimes improvise around the chord progressions of precomposed songs, incorporating variations on recognizable themes, riffs, and rhythms while allowing for unexpected detours of unpredictable duration. This is arguably a progression of the guitar solo, a feature of traditional rock music."

Bands you have no doubt heard of that fall into this category, in no particular order, are the Dave Matthews Band, Widespread Panic,­ and Phish. The Grateful Dead, of course, is its founding father. Anyway, I digress. Cleverly, Bonnaroo organizers know a thing or two about pigeonholing, so they also invite a multitude of big-name acts across a diverse swath of genres (2005 saw Modest Mouse, Black Crowes, the Frames, Kings of Leon, Jurassic Five, and De La Soul), and suddenly, everyone within a 1,000-mile radius descends upon middle Tennessee as if it were a bus stop on the road to the musical heavens. Naturally, nothing short of an apocalyptic backstage will do.

WHILE THE DAVE MATTHEWS BAND is tearing through a Friday-night headlining set full of exercises in the kind of musicianship most artists only dream of (yes, they are that good live), the chosen few are living it up in Artist Hospitality, though few is a relative term. Bonnaroo reports that in 2005, some 3,000 people had access to this area, a small village located a stone's throw from the main stage. Behind its two security guards, who put up with less malarkey than a weather-beaten grandma guarding her precious, secret recipe for peach cobbler, you'll find a world that specializes in all things free.

There are Clif Builder's bars (protein), Sambazon Açai (antioxidants), and Starr Hill Amber Ale and MoJo Lager (intoxication) - which make up a meal for most musicians. There are free Xbox games and classic arcade games like Galaga and Asteroids. There are two masseuses who I'm quite sure didn't take their hands from the strained necks of musicians, production crew, and, of course, journalists, for four days straight. And while there wasn't supposed to be free Patron tequila, the Patron girl saw to it that the bar was fully stocked with that too.

Outside the tent but within the same stomping grounds, there are Lee jeans and jackets and Timberland boots, batting cages,­ and a PGA golf simulator. Did I mention this was all free? I flirt with the Lee Jeans girls for a free pair of jeans - not being a musician and all - but they only have size 31 waists left. Now, I'm normally a 33, but rock stars wear their jeans tight, right? So I decide to squeeze into them anyway. And just when I think my hips are being hugged worse than anyone else's out here, I see the members of Southern-revival-rockers Kings of Leon. Their jeans are so tight, 31s would look like clown pants. I'm told theirs are size 27s and slink off cursing their names.

ON SATURDAY MORNING, the media is treated to a private acoustic set from singer-songwriter Iron & Wine in the Press Tent, located across a muddy road from the Artist Hospitality Tent. This Bonnaroo tradition is a gem for those with access to the tent, which begins with journalists but extends on up the VIP-pass ladder, mainly because musicians see it as a much more casual gig than the one in front of the masses. Samuel Beam, who is for all intents and purposes Iron & Wine, didn't even prepare a set list.

"What do you all want to hear?" he asks. Of course, one reporter just has to say it: "Freebird!" "Don't tempt me," answers Beam, before checking to see who's ringing him on his cell phone. Try getting that kind of intimacy on the main stage. Later that afternoon, both Kings of Leon and professional surfer/singer/songwriter Jack Johnson work the masses into a frenzy from the Which Stage.

Johnson, who has segued professional beach bumming into a multiplatinum recording career, sees the benefits of both sides of the pass debate. "When you're out in the crowd and you don't have a pass, you're a part of the energy of the crowd, and it's always fun," he says. "When you have a pass, you get to watch from the side. It's a lot more comfortable sometimes, but you don't feel the energy quite the same."

He has a point. I've seen some of the greatest bands in the world from the side of the stage, where the sound leaves much to be desired. On the other hand, watching 50,000 people from the same angle as the band is pretty cool- plus, you don't have to pay $5 for a Budweiser. At Bonnaroo, though, it all comes down to the Artist Hospitality Tent.

"The difference at Bonnaroo is, it's really a fun festival to be backstage," continues Johnson. "A lot of festivals have uptight security and the interaction between the bands isn't all that great. Everybody is being hurried everywhere. [But here] it's really laid-back. They are more concerned with the vibe than with everything running perfectly."

AS WIT MOST three- and four-day music festivals, the vibe out in the crowd by Sunday is somewhere between "Subterranean Homesick Blues" and "I Don't Like Mondays." Backstage, it's more like "Rockin' in the Free World." In the Press Tent, the media is treated to bagels and lox and all the fixings - a meal the general populace couldn't dream of getting.

I wander over to the comedy trailer - yes, you need a pass for that too - where ex-Saturday Night Live comedian Jim Breuer is goofing off with some fellow jokesters. Breuer is doubled over in laughter as he remembers a Wiffle-ball match he and his cohorts had with a group of fans earlier in the festival. In order to have the match, he had to invite the fans from festival land to candy land for a few hours. (He wasn't about to cross over the opposite way.)

"Let me tell you something," he says. "Right now, I need some rest. I'm in my 30s, so I'll gladly take the backstage with the pass and rest. When I'm in my 40s, I'll venture out and go back to the mud side."

Later that afternoon, one of Bonnaroo 2005's biggest draws, Modest Mouse, is pounding out one indie-rock staple after another on the Which Stage. In the VIP rafters next to it, I meet a rare breed at a festival like this: a genuine fan who has managed to finagle a pass, getting a taste of both worlds in the same festival. Dylan Stacey is a 19-year-old University of Kentucky freshman - who better qualified to have the final word?

"Being out with everybody else, it sort of felt like you were more at home and could actually meet and understand where everyone else is coming from," he tells me. "Out there, people will say, 'Do you want to stand with us? Share our mat?' In here, you find your own table, get your own drinks, and nobody really pays attention to you."

Welcome to the music business. So having experienced both sides, where will he be in 2006? "If I had to choose, I would love to be out with the masses - if everything were free like it is when you have a pass. But it's not," he says. "When you can walk in here and get a bottle of water for free - and it costs $2 out there - it's awesome. So, I'd choose in here because it's free. That's just the kind of guy I am."

Me too, Dylan. Me too.
BONNAROO 2006
When: June 16 to 18, 2006

Where: Manchester, Tennessee

Who: Radiohead, Beck, Tom Petty and the Heartbreakers, Bonnie Raitt, Death Cab for Cutie, Bela Fleck and the Flecktones, Sonic Youth, Son Volt, Matisyahu, Blues Traveler, Gomez, and Medeski Martin and Wood, among others.

What to Bring: According to Bonnaroo.com, rain gear, a hood, and an extra pair of shoes, sneakers, or mud boots; bug spray, blanket, sunscreen, hat, plastic containers, extra toilet paper, lantern or flashlight with extra batteries, portable radio, a flag or balloon to identify your campsite, a small luggage lock for your tent, earplugs, extra trash bags, a camera (disposable), and a pen and paper for names and addresses, memories, and set lists.

Info and Tickets: www.bonnaroo.com