Ri-li Game.

The OLPC has keypad buttons that would make sense to
map.

On the OLPC the keypad buttons are mapped to the numeric keypard:
http://wiki.laptop.org/go/Developers/FAQ#Directional_pad.2Fbuttons
http://wiki.laptop.org/go/Pygame_wrapper#Keyboard_and_Mouse

AFAIK, it would make sense to have the left gamepad keys (KP2,KP4,KP6,KP8)
work as the regular arrow keys do, while the right side keys have
rotational keys (KP1,KP3, "V" and "X" symbols, clockwise and
counter-clockwise respectively). The remaining two keys (KP7,KP9) could
then be used for game menu navigatory purposes. "[]" is a nice pause, and
"O" for menu?