Funniest cameos?

[phil marlowe]

jim jarmush and lou reed in blue in the face
snoop dogg in half baked

[Sigur Rós]

snoop dogg in half baked

This one is actually THE funniest cameo!

[budgie]

And I'd have to say Brad Pitt and Matt Damon made me laugh like no other in Confessions of a Dangerous Mind.

The only good thing in that movie. Totally out of place and gratuitous, but it woke me up for an all-too brief moment.

Ed Norton's first appearance in Frida did that too, and worked as a jolt out of the period feel, which was great. Shame they had to turn it into more.