Is the Mr. Show theme inspired by Lumpy Gravy?
EDIT, for Mr. Smitty: the Mr. Show theme was written by Mark Rivers drummer for the Cavedogs, who I'm now interested in; also, you will someday fight cavedogs. You can buy a recording of the Rock Coaches (funny name) playing it here. Or you can listen to the whole track instead of buying it.
Lumpy Gravy is a Frank Zappa record and song. You can listen to a snippet of Keith Emerson playing the title theme from Lumpy Gravy here (track 13). And it's track two here, on the new album that I covet most in the world.