I bought another Raspberry Pi, this one for playing around with some embedded I/O stuff, and also to have a spare. This time I got the Adafruit Raspberry Pi starter kit, which has a lot of nice accessories for a good price.
Also, I set up my electronic workbench again since the electronic accessories were beginning to clutter my actual desk.
I set up the new Raspberry Pi basically as before, but of course, with a new IP address.
I also set up the Adafruit GPIO adapter and breadboard (included in the Adafruit starter kit). The instructions are very clear and easy to follow. I also installed the Adafruit libraries, git, Python-dev and a few other recommended packages as instructed on that page.
And installed and built WiringPi. That's a C library for accessing the GPIO, which I thought I might need later. Also, it has a command line utility for accessing the GPIO, which is handy for testing.
Fun stuff! It only took a minute get compile and run a C program to blink the light, which is, of course, the equivalent of "Hello world."