Making Arduboy mockups of classic Commodore games is great way to spend an evening. Dicky's Diamonds was a game published in 1983 by B. O'Shaugnessy for the Commodore 64. The game scales down handsomely to the Arduboy's scale and 1-bittyness.
BC's Quest for Tires is another favorite I can enjoy on the Commodore 64, Colecovision, and the Atari 8-bit. I am really happy with how my Arduboy mock-up turned out.
I recently got an Arduboy and I think it's a pretty fantastic little device. Inspired by the very low resolution display (128px x 64px) I decided to do a few mock-ups. My Jumpman port looks doable if only to punish the gamer's eyes. I LOVED Jumpman on the C64, Atari 8-bit, and Colecovison.