I dunno if Primus would go well with classical...they're seperated by universes in composition style...

Primus and Radiohead. Why not?

Radio head, Pink Floyd We'll have an art rock extravaganza.

Louis Armstrong and Joe Satriani...I'd crap my pants.

Luciano Pavorotti and Metallica... (sing "Master of Puppets" to the tune of "La Donna e Mobile)