Early in my programming career (actually, it's still early in my programming career, but
earliER), I wrote a game called "Fall".  It was a cute little game where you caught falling
pi symbols.  I later added Stars of Death which killed you if you touched them.  For three
months my girlfriend had my calculator, and when I got my hands on my friend's calculator
I went mad with repressed inspiration and wrote this game in MAYBE 5 minutes.  It's cool.
Either catch falling smiley faces or press the right number quickly enough (that one is
HARD).