I recently discovered you can use the pins on the Raspberry Pi to programmatically toggle switches! As a software guy, I find that magical. I ordered a cheap 8-relay board [1], and I'll hook some stuff up to it and turn my house devices on and off via the internet!<p>[1] <a href="http://dx.com/p/8-channel-5v-relay-module-extension-board-for-arduino-avr-arm-51-140703" rel="nofollow">http://dx.com/p/8-channel-5v-relay-module-extension-board-fo...</a>
See <a href="http://www.cl.cam.ac.uk/freshers/raspberrypi/tutorials/os/" rel="nofollow">http://www.cl.cam.ac.uk/freshers/raspberrypi/tutorials/os/</a> for some really good tutorials for making a toy OS from scratch on your Raspberry Pi.