Since Bonnaroo began in 2002, a programming lineup staple has been the SuperJam. Equal parts spontaneity and careful planning, this "anything goes" set brings cross-genre performers together with the unified goal of delivering a funk-filled, memorable set (check out our top 5 SuperJams ever here). 

It's fun to watch the chemistry between the always-unusual SuperJam collaborators unfold, and this past Saturday night, it was clear that everyone wanted to get in on the action. To kick things off, actor and comedian Zach Galifianakis introduced the Jam (after teasing the crowd with a Wi-Fi password announcement), and Mad Men's Jon Hamm joined him for an as-stirring-as-possible rendition of "We Are The World."

zach galifianakis and Jon Hamm (Don Draper) singing we are the world last night at #SuperJam 😂

A video posted by ᕼIᑭ ᕼOᑭ ᗰIKE / ᕼOT 97 NYᑕ 📻 (@hiphop_mike) on Jun 14, 2015 at 8:04am PDT

2015's theme was "80's throwback," so, fittingly, Chance the Rapper helmed a cover of Biggie's "Juicy," while Pretty Lights, DMC (of Run DMC), Rob Trujillo (Metallica), Jack Antonoff (Bleachers), SuperJam favorite Reggie Watts, Jamie Lidell, John Medeski and more rotated in and out. No night honoring the 80's would be complete without the decade's icon Corey Feldman, and he was indeed in attendance and hopped on stage during "Eye of the Tiger."

Just across the way, Ed Helms surprised the crowd at Mumford & Sons and stopped by with his banjo for "With A Little Help from My Friends." Yes, Andy Bernard really played the banjo. Helms and Galifianakis co-starred in "The Hangover" movie series; we wonder if they met up for any off-stage antics.