Back when I was in university we had a small course on Limbo/Inferno because of a connection my university (RIT) had to bell labs. I took the course in... 1998? and wrote a version of Tetris for limbo. The code was awful, but did find a bug in the Tk implementation. This lead me to my proudest/most embarrassing programming moment - apparently, my code ended up in front of Dennis Ritchie, who thought the code was terrible. Whatever, Dennis Ritchie looked at my code!
Anyways, here's the awful code: https://github.com/adamf/limbotris