I’m playing around with a .NET development board with great fun for home automation. They come in all price ranges(some very simple and there are the ones with screens, wifi and so on) and support a compact .net framework and have a lot of sensors and relays to add on to it!
NetDuino
My own project at home is that I just had a on/off switch for my warm water. I do control it with my netduino board by a fixed times but I can also switch it on from a web browser. Next version is for it to not switch on if there have been no movement in my apartment for a while so if I go off for holiday I don’t have to switch it off. Also bought an servo to open my window if temp go over a certain degree :).. Next will be to have some kind recognition if a lady enters to start the soft music and the disco ball spinning!