ok your just crazy if you wanna play classical on a kazzo but if you insist. come of with really pointless lyrics to a classical piece and sing them into the kazzo. see if that works
Ï could imagine Grieg's "'In The hall Of THe Mountain King'" working well on Kazoo..or Wagner, perhaps.
You may have to supply the audience with free drugs and booze to get a really positive result, of course.