The last thing I was expecting from a game built on relativistic physics principles was a gentle allegory about the afterlife. But that's exactly how A Slower Speed of Light starts off. The little protagonist in this title from the MIT Game Lab actually dies right at the start of the game and has to pick up objects that help him along to becoming light itself.
The PC/Mac prototype offers players a look at how the world would appear when traveling at lightspeed, complete with Doppler shift and time dilation. For a game made by straight-up certified geniuses, it's a really approachable experience. It's a free download, so if you're the least bit curious about what it's like to warp one of the universe's greatest constants, definitely check it out.
A Slower Speed of Light [MIT]