Bouldered a bit in college, feel like code challenge sites like Project Euler are like a programmer form of bouldering. you fail a few times, gain an insight, make some progress, finally get it, then feel a big rush of accomplishment.
Interesting comparaison, but bouldering problems relies on physical-traits that are harder to move up than the psychological-traits needed in Project Euler. ( think of size, balance, synchronicity ... ).
... but OK some PE are now too hard for me. Training during college would change the game.