We thought the Meggy had some serious potential. The open serial port is ripe for the plucking, but has thus far been fairly unused. Here’s directions on how to make your own serial cable capable of connecting two Meggies. Basically, it is just modifying an audio cable, used to connect CDROMs to the motherboard. The cool thing about this is that the resulting crossover cable should work on any Arduino that is programmed via an FTDI cable.