paperwallet
Arduino Based Bitcoin Paper Wallet Printer
Demo at http://www.youtube.com/watch?v=noW77GqmNBQ
The sketch compiles is larger than 32,256 bytes so you'll need to either burn it using a programmer (don't forget to disable bootloader on reset)
e.g.
avrdude -v -patmega328p -cusbtiny -U hfuse:w:0xDF:m
Or disable some functionality (e.g. random number verification)