As part of the Ludum Dare competition, animator Tom Campbell went all Tom Hanks on his entry by creating Adrift. Skirting the game/non-game conversation for a moment, Adrift falls somewhere between interactive wallpaper and Tamagortchi. You are, well, you and you are stuck on a boat for the foreseeable future. The nifty thing is the weather conditions match your location's weather patterns and the sun rises and sets based on your computer's clock. That means if you're up at 6am, you can catch the sun rise.
No word if aliens show up in the third act, but we wouldn't hold our breath.