A small startup here has tucked a Bluetooth RF transceiver and protocol-translation FPGA into a cartridge format compatible with the Nintendo Game Boy Color and Advance platforms. X-Tra Fun Inc.’s intent is not just to provide a Bluetooth link between gamers in one room, but to turn the Game Boy platform into a de facto PDA. The handheld game device would be able to synchronize with a Bluetooth-enabled PC, send and receive e-mail, send text messages to a cell phone and, eventually, receive streaming video at several tens of frames per second.