Their cover shows usually always have tons of big name special guests with them though.
Not really. I've seen them live three times now. One time, Joey from NSync came out and sang a few songs. Another time, Michael Star played bass for Man in a Box. I don't think anyone came out for the third show I saw. I heard Dane Cook will go on stage a good amount.
3/13-Larry and His Flask
4/26-Good Luck Thrift Store
4/27-Trampled by Turtles