Awesome Games Done Quick
This is a bunch of people who are experts at "speedrunning" games (getting through them as fast as possible, sometimes completely glitching/breaking the game in order to do so).
They do a bi-yearly charity stream for a full week, 24/7, in which they have people stream "speedruns" and collect donations for charity. Last January, they pulled in almost $460,000 for the Prevent Cancer Foundation, and last June they brought in about $255,000 for another charity.
This is surprisingly fun to watch, and they generally do a pretty good job of explaining what's going on, calling in game developers to answer questions, and other things.
Pretty interested to see the Dishonored and Zelda speed runs.