Nyan Cat had a game and we covered it here. It turned a simple flash animation into an interactive flash game. What was so mesmerizing about the game? Partially its soundtrack, which is the same as the animation it was based on. In this video, you can find an amusing rendition of that, along with other memes that are rendered on screen.
There used to be an embeded media player here, but it doesn't work anymore. We blame the Tumbeasts.
[Video via Tomorsketches]