I'm a computer science student in college who's been obsessed with optimal code since long before college. My favorite langauge to use in code golf contests is CJam.
If you want to see some (hopefully) interesting answers, here's a short list of the answers I've produced that I'm most proud of:
- ICS Maritime Flag alphabet
- Pure Sourcery - Shaping programs that output the digits 0 through 9
- Keep the unique characters down
- Generate a pair of integers from a non-negative one