I went to their show Saturday night in Dallas at the House of Blues. TRULY AWESOME EXPERIENCE!!!!! They were rad and the projection show they had was hilarious.
There's an actual band. They play the cartoon behind them on the screen. The show (which was animated before) matches up with the music (which is being played live).
The guy who thought up the band/makes the show/wrote the music sings in the voice of the cartoon lead singer, and plays lead guitar. The drummer's the same from the album. They hired a rhythm guitarist and a bass player.