It may already qualify as an internet meme by this point, but the Hulk At The Tropicana, 1965 video on YouTube really may be the funniest thing that I've seen in a long time. The best part is when Hulk starts making conversation with the audience: "Yuma? You have good soldiers there, Hulk fight them once." Click through for more of ol' greeneyes charming the audience.
I saw him do a spoken word show in Berkeley back in '93. He wasn't supposed to do any songs, but after the show he hit Jupiter down on Shattuck and just started belting out tunes. Then he threw a BART train into Oakland, but I'd left by then to study for a physics midterm, so I missed it. Ain't that how it always is?