Where would I be at work without Youtube? It doesn't help that I have dialup at home.

Greg Patillo - beatboxing flautist has a few videos.
I also check bestofyoutube.com reguarly.
I like watching skits from funny shows like Saturday Night Live, Mad TV, or Whose Line is it Anyway.
I also like looking up music, especially quirky stuff or parodies/covers of popular music.