Perhaps this isn't the best place for this question, but I know that this is a community of hackers and I can't think of a better audience for it.

I've been eyeing a Raspberry Pi board for some time, but I can't think of what I'd like to do with it. I have NO background in EE - I'm really just a programmer. But I think it would be cool to, say, somehow make a raspberry pi turn my house lights on and off remotely (or via some timer). Now I know that there's the GPIO port on the Pi, but... how do I use it? How do I wire it up?

I think that's my biggest challenge. I have lots of old electronics, and potential uses for the Raspberry Pi, but I haven't the faintest clue about how to wire it all together. Perhaps I'm way out of my element, but I don't even know where to get started. I'd love to see very, very simple Rapsberry Pi hacks using the GPIO ports to interface with existing electronics, so I can get some ideas and so I can learn.

I guess what I'm saying is: I think the Raspberry Pi is really cool for hardware hacks, but I've not got the faintest clue about where to start - only that I want to start somewhere! Does anyone have any ideas?