Check this out. This is pretty cool. http://www.qubetubers.com/event/ It is half over but they have raised over $22,000 for Childs play charity so far. I donated $50 early on and have played a bit in the servers they use and there are so many people and great buildings in there. The event largely speaks for itself but here is some info from the FAQ.
QubeTubers is a humble little gaming community. Started in Oct 2010 as a branch off of the MineCraft Girl Edition livestreaming fanbase. It quickly became a community of like minded gamers who enjoyed making a difference, either by raising money for charity, raising awareness for IndieGames, and being there for each other through thick and thin. We love pulling together our resources to create a foundation, or venue if you will, for events such as the 48 Hour Minecraft Marathon for Child's Play.