[angrycoder]

I'm not John Carmack, but I spent 2 hours today trying to implement basic cryptography ciphers in Racket. What was the immediate benefit? Nothing, but it was fun.

[prezjordan]

During Hurricane Sandy I used the last of my MacBook Air's battery to code up a Huffman Coding processor in Haskell. Same reason: no reason, just fun. (Hell of a way to pass time, too)

[pjmlp]

Same here. Recently I just re-wrote a language runtime from a toy compiler I had, from C to Assembly.

Was a rational thing to do? Maybe not, but it was fun to do.