our 3 largest exits to date have been Wildfire Interactive (acquired by Google for $350M, summer 2012), MakerBot (acquired/merger with Stratasys announced for $400M, summer 2013), and Viki (acquired by Rakuten for $200M, summer/fall 2013).
500 Startups was an early investor in all three companies (and I also invested in the Wildfire seed round via Facebook fbFund, which I managed in 2009 on behalf of Founders Fund and Accel).