It's a little hard to tell because the only place it's available is a less-than-helpfully-formatted Myspace page, but here's the lineup for the Chicago edition, set for August 1-3, 2008.
Tiny Masters of Today
The Dream Jam Band
The Q Brothers
The Terrible Twos
Peter DiStefano & Tor
Suzy Brack and the New Jack Lords
Paul Green School of Rock All Stars
John Yost's Rhythm Revolution
Considering one of the few bands I'm not familiar with - Suzy Brack and the New Jack Lords - is pegged as "tiki-punk," it's safe to say the stage will bring no small amount of rock.