For anyone who has have not played with a microcontroller yet, here is your chance to try one out for a very decent price.
Popular Science has a article about the RBBB (Really Bare Bones Board) - the most minimal (to date) clone of the Arduino. This board fits the 16MHz Atmega168 and the most minimal of support components onto a PCB barely larger than the IC itself.
Ladyada has had a slightly more feature-filled equivalent available for a while, the Boarduino.
For more info on the Arduino, go here.
Oh, and there WILL be one included in my robot.