Home automation gadgets for free

mamadrum writes "Firecracker is giving (today only) away a starter kit of PC controlled home automation relays and software. It uses a wireless connection between the PC serial port and an outlet, then modulates control signals on the house AC wiring. Seems to be an example of "give away the razors and charge for the blades" since you only get one relay. Still, adding relays is cheaper than opening up my walls to put in 10baseT. Old tech but decent price. "It's 5.90 for the shipping. Anyone played with this before?