I am stupid. I returned to my powerbook this afternoon to find the keyboard locked in numberpad mode (i.e. some of the letters are mapped to numbers and the rest of the letters disabled to mimic having a numberpad like the one on the far right of a full keyboard).
"Great," I thought, "I accidentally hit some key combo to do this and I can't figure out how to undo it." After mashing the control keys for a while and vainly searching for a setting in the keyboard preferences I actually cut and paste using the mouse the search term "aPPle keyBoarD NUMBer Pad" and tried to find help but to no avail. Eventually I gave up and decided to log out and log back in to reset it.
Except that when I tried to enter my password to log in I was still in numberpad mode. At this point I started cursing at my computer for about 5 minutes. Then I noticed the faint green light on under the "num lock" button.
So yeah, I'm stupid.