This video is simply amazing. I've spent more than my share of time playing Super Mario 64 and Super Mario DS, but this guy knows tricks I never dreamed of and seems to be able to jump with godlike accuracy. If you've ever played this game, you owe it to yourself to watch this. I'm just speechless.
UPDATE: Well, this isn't actually a video of someone playing. It's a tool-assisted speed run, which is something that I had never heard of. As I understand it, they use an emulator and some software tools to enable the player to redo certain parts over and over, and to play at less than full speed. Sometimes they play at 5% normal speed, or even frame-by-frame. Why anyone would want to do this is an interesting question. I guess some people really love these games and want to try and come up with the "ultimate" run-through. Still, many of these moves aren't possible for actual human beings to perform, so in some sense they don't reflect what the game is actually supposed to be like.