I've got an immense amount of respect for those dedicated souls who put together Speedruns, although I've never quite had the monomaniacal (and I mean that in a nice way) dedication neccessary to try one myself. The concept of matching up speedruns to charity, though? That's not just monomaniacal; that's sheer genius.
Indiegames highlights the charity marathon currently being undertaken by the Speed Demos Archive under the Awesome Games Done Quick banner; the idea is that as you watch games being completed at near-impossibly fast rates, you also donate to a good cause — US Cancer research — as you watch. So once you're done watching the embedded video above, don't forget to donate as well. The plan is to run through 110 games in 150 hours, concluding on January 12th US time. [Awesome Games Done Quick via IndieGames]