As the annual Bonnaroo Music & Arts Festival rolled into Saturday (June 15), there was a pervading air of mystery. Whether it centered on what was going to happen at the impromptu Jack Johnson headline set, or what outfit Bjork would bring to the stage, there was plenty for fest goers to sink their curious teeth into on the second full day of programming. Here's a recap of the more memorable events, among them endlessly talented and entertaining R. Kelly's U.S. festival debut.

Pitch Perfect: One of the major challenges at any outdoor rotating-set concert is properly lining up the sound for a band with rich melodies and harmonic power. Nobody on the current circuit fits that description better than Dirty Projectors, who were able to soar during their This Tent performance with their undeniable voices rattling and flourishing. All in the face of having been mildly upstaged only two hours earlier.

Cover Crazy: Everybody loves a good cover, but sometimes, a little diversity is nice, too. Solange took the stage a good two hours before Dirty Projectors, so she had first crack at keying up their hit 'Stillness Is the Move.' They must play a lot of indie rock records at Carter-Knowles family gatherings. Meanwhile, Steve Miller may not have been in attendance, but his presence was well felt as Gov't Mule and Jack Johnson saw fit to run through their own reworked versions of 'The Joker,' aka the most appropriate Bonnaroo cover choice imagineable. And just for added measure and tribute, Johnson worked through a healthy sing-along rendition of Mumford & Sons' 'The Cave.' But if there were an award for best cover, the trophy would have to go to Portugal. The Man, who closed their Which Stage freak out with the closing chorus of 'Hey Jude,' which was still fresh in everyone's minds from the night before.

Best Quote: OK, this was less a quote than a sung request. R. Kelly paused midway through his late-night party on the Which Stage to humbly ask, "Can I get a towel, to wipe my face? I"m sweatier than a motherf---er." This was repeated in his signature croon over several measures.

Worst Conflict: When 7PM hit, many were faced with a particularly difficult choice between seeing Bjork and Beach House. Chances are if you like the former, you enjoy the latter, too, so what to do? The first half of Bjork's dynamic and arresting What Stage show saw the artist backed by a full choir of exubernt young women as she beguiled in her crystalized facemask. If you still had the energy to make it to The Other Tent on the complete opposite side of the festival, the reward came in the form of Beach House's dreamy song constructions. Sometimes, its not the conflict at a festival, but what you make of it.

The Mighty Superjam: One of the many unique traditions carried on by Bonnaroo since its inception as been the Superjam, where artists are plucked from the roster and put together create something never before seen. This year, Bonnaroo mainstay Jim James was given the keys to the late-night ride as he along with John Oates and a slew of legendary funk and soul musicians absolutely tore up the This Tent field before them. Highlights included an incendiary cover of Prince's '1999' and a guest turn from R. Kelly, fresh from his set minutes prior. It was a perfect way to cap the last late night of Bonnaroo 2013.