[Bunnyboy] pulled off some wizardry with this custom NES cartridge. Inside is the mainboard for a Game Boy as well as his own custom PCB with the comb connector needed to interface with an original Nintendo Entertainment System. In his own words itís ďa Super Game Boy without the SuperĒ. The expansion port to for the handheld is still accessible for some head-to-head Tetris or use with the obscure Game Boy printer.

http://hackaday.com/2010/05/11/origi...ame-boy-games/