A few things really stuck out this year, though, as we reviewed things following Tom Petty's rain-drenched, festival-closing 2 1/2-hour set. Here's a look at five:
Rock `n' roll will never die: Those who think rock `n' roll is irrelevant or even dead need to pay a visit to the farm. It may be showing its age - eternally rocking Paul McCartney and Petty and The Heartbreakers were the two most prominent headliners - and electronica and hip-hop are elbowing their way in - witness start turns by Macklemore, Kendrick Lewis and A$AP Rocky, who brought more than 20,000 fans to a tent designed to hold 5,000. But it's really still rock `n' roo.
Just ask Derek Vincent Smith, the DJ who performs as Pretty Lights. Smith had one of the most anticipated and well-attended events of the weekend early Saturday morning, spinning tunes for tens of thousands of wild, scantily clad and costumed revelers until nearly 4 a.m. He saw something interesting as he worked his way through his set, however.
"From my perspective, I really noticed a massive response to my classic rock remixes," Smith said. "So Bonnaroo hasn't changed too much, you know what I mean? My Pink Floyd remix, my Led Zeppelin remix, my Steve Miller Band, stuff like that, people went crazy. I wasn't initially planning on venturing into that territory, but I was trying to read the vibes."
Smith decided to spend parts of three days in middle Tennessee checking out the festival. He said it's been one of his best experiences.
"Everyone's there," Smith said. "It's not Coachella where everybody leaves and they go to their condo or whatever. Everyone's out there sweating, getting smelly together. Even with the electronica and hip-hop and all that really becoming a big part of it, it's always going to be a hippy festival in the end. That's awesome."
Macklemore is for real: Think the popularity of Macklemore & Ryan Lewis is just a fad built on a novelty song? You should have seen their show Sunday at Bonnaroo. Filled with humor, non-stop energy and the duo's recent hits, including "Thrift Shop," the show was something of a revelation.
"I like Mack," Lamar said as Lewis' bass rattled the walls of his backstage trailer. "I've hung with him a few times. Cool dude, man. He's taking over."
And that's just what he was doing outside. In a soon-to-be-classic YouTube moment, Macklemore saw a fan in the crowd sporting a spotted fur coat similar to the one the Seattle rapper features in the "Thrift Shop" video.
"Can you take off that fur jacket and crowd surf it up here and let me take a look at it?" Macklemore said. The fan sent the coat toward the stage and security tossed it up to the rapper: "You know, this doesn't smell as bad as I thought it would. It smells like weed and malt liquor."
He put the coat on and sent the crowd of 40,000-plus at the main stage into a frenzy with the help of a live horn section as he launched into "Thrift Shop," the group's breakthrough hit that's launched a six-month run to pop stardom. Even a pop-up thunderstorm couldn't slow things down and Macklemore wrapped it up by crowd surfing.
HAIM is next: HAIM already had a little buzz rolling into Bonnaroo after time spent on the road with Mumford & Sons and anticipation for the sister act's debut album building. Their well-attended Thursday afternoon set should add to the clamor building around Este, Alana and Danielle Haim.
On their previous EP releases, the band came across as more a girl group with complex harmonies and a hip-hop influenced sound. On stage, though, they're something very different. All three play instruments, have the ability to rock as they showed on a Fleetwood Mac jam and finished off their set with a rousing drum circle that fans were talking about a day later.
The best moment, though, had nothing to do with music. Este Haim shut the group down about midway through the set and pointed at a sign in the crowd: "There's a little boy holding a sign that says, `Kiss me, Este."
And she did, bringing the toddler who wore a large yellow noise-blocking headset onstage where she and her sisters posed for a picture with him.
"I'm engaged now," Este Haim said.
Two by two: Jack White and The Black Keys have mostly moved on from that two-man band thing, but a wave of guitar-and-drums duos continues to roll through rock `n' roll. At least four were on display at Bonnaroo - Japandroids, JEFF the Brotherhood, Deap Vally and Beach House.
Vancouver, British Columbia-based Brian King and Dave Prowse of Japandroids turned in one of the festival's most raucous performances Thursday, and they did it with just two guys bashing away. King plays guitar and sings most of the songs and Prowse plays drums.
"There's a lot of positives and negatives to it," King said after the set. "Like there's no third, fourth or fifth person to break a tie. It's more like a relationship. You have to find some kind of middle ground to make it work or it doesn't work."
King said bands such as White's White Stripes and the Keys - both nominated for album of the year at last year's Grammy Awards - showed young rockers the possibilities by making music more accessible.
"If you have a close friend who's fun to jam with, then you can do it too," King said. "That's it."
Inspiration comes from everywhere: Members of Alaska-via-Portland rockers Portugal. The Man played on the festival's second largest stage a week after their new Danger Mouse-produced album "Evil Friends" hit the streets, raising their profile as high as it's been.
But they were more stoked about the strange guy who came out and made a crazy appearance on the accordion during the band's set Saturday. That guy was Weird Al Yankovic, the timeless rock `n' roll jester.
Turns out Yankovic, in all seriousness, was a huge influence for John Gourley. The lead singer said when he and his bandmates first made their Myspace page, it listed Yankovic as their only influence.
"He really is," Gourley said. "He introduced us to music. Weird Al was something that kids would listen to. It's funny, super funny, smart. It's just kind of jokey. I remember hearing `Smells Like Nirvana' before hearing `Smells Like Teen Spirit.' That's how it really worked. I think it's just such a cool thing how he introduced us to so many cool bands. Even Queen - `Another One Rides the Bus.'"
Follow AP Music Writer Chris Talbott: http://twitter.com/Chris-Talbott.