A buddy of mine's brother programmed the game Jetman, a game you can play for free on Facebook. The game, in my opinion, sucks, but he makes $2,000 a DAY off the ad revenue (Facebook lets game creators keep 100% of the ad revenue for themselves as they figure the more games they have on their site the better, as it creates more sign ups). 21 years old and making $2,000 a day for what is essentially no work (he makes occasional upgrades or patches, but for the most part just sits back and lets the money roll in.)