Weather station
It's not exactly a computer toy, yet, since I don't have the CO interface, but I got a really cool wireless weather station for Christmas. It's a LaCrosse WS 2010, and measures outside temperature, humidity, windspeed, wind direction, rainfall, barometric pressure, and indoor temperature and humidity. The display unit is a very attractive LCD panel. It displays a 24 hour graph of pressure, and makes a weather forcast based on the pressure history. (Just like the old salts with their "glass".) Various computed values like wind chill and dew point are also available, as are zillions of alarms, max/min readings, etc. The coolest part is that it's all wireless -- uses the 433 MHz channel. You just attach the sensors to a mast in a suitable location, and you're done installing it. Sensors are all solar powered. I was tempted to put it on my boat next spring, but the data is only updated on a 3 minute cycle, so windspeed and direction wouldn't be very useful 3 minutes after a tack or wind shift. Oh, one other "cool" part -- I nearly froze my fingers off installing the sensors on a windy, snowy, -4 degrees C day, but had to show appreciation for the present!