I've always thought that The Firesign Theatre's work was actually a precursor to HBO's Mr. Show.  I haven't seen that correlation made before (a little more research might prove me wrong), but it seems very obvious to me.  So my commenting here is just to tell fans of the Firesign Theatre that they should check out the Mr. Show dvd's and that the Mr. Show fans oughtta check out the Firesign Theatre's albums.  Great stuff, in either direction, and Don't Crush That Dwarf has always been my favorite.  (First season of Mr. Show was my favorite of that series, in return...)