Have you ever wanted to control the lights in your house from your computer? It's actually fairly affordable to do so. You can even control sprinkler systems, automatic window blinds, motorized projection screens, etc. You need two pieces of hardware to get started. A controller, which connects to your computer; and a dimmer switch. I'm using SmartHome Insteon products in this example.
Step 1: Install the switch
Follow the instructions provided on how to install the switch. The switch I'm using is Insteon brand, but there are other types of remote controllable switches such as X10. These switches require the neutral line to send signals (commands) over. If your switch box doesn't have a neutral, you're in trouble. Try contacting an electrician to see what you can do.