Now that Kat's robot science fair project is done, we're slowly turning our attention to the Raspberry Pi and Beaglebone Black boards she has. I'm actually installing Raspbian on the Pi right now, it's about 50% complete.

Kat really wants to try crunching with it, so for those that know more about this than I do: what would be the best project to run on this thing? Not sure what kind of math the little ARM CPU does best, but here's our options it looks like:
Asteroids
Collatz
Einstein
Enigma
YoYo

Which do you think would be most suited to the Pi and its [limited] crunching capabilities? Thanks!