Our friends over at Ponies Live Now! are having an event on Sunday which they have called the "Elements of Charity". It's a 24 hour NES/SNES marathon to benefit the Humble Brony Bundle, and they have over $300 dollars in giveaway prizes for random viewers! They will also have various Brony celebrities attending the event (I was invited, but unfortunately won't be able to attend), and if you donate enough to them during the livestream, you will be able to request a game for them to play.
If you want more detailed information about the event, please go here. The livestream will take place over at http://www.twitch.tv/ponyslivenow, and on March 11-12, starting at 12pm PST.