Just after Stillwater (well, guitarist & singer) gets in the fight about the crappy stillwater T-shirt, you see William and Russel (guitarist) walking by themselves. Watch the green VW Microbus go by in the background.. in the very next scene, it goes by again. Then finally, the driver of the Microbus just pulls up (for the 3rd time im guessing) and asks Russel to come over to the party.

Hmm maybe he was just a big fan circling the block, waiting for the right time to ask ?!?!