I'm working on learning the Arduino, an electronics board with many interesting application for getting the physical world and the digital world to interact. It has been used to create interactive art, musical instruments, mass transit alerts, rc helicopters and super accurate espresso machines along with tons of other things. It has been used to take input from websites, streams of water, wii nunchucks and various items you might not expect.
For now, I'm just blinking lights and sounding alarms. I've given it three patterns for blinking 5 lights and am demonstrating the ability for me to instruct the arduino which pattern to use for the blinking. I'm also pointing out some other interesting things I stumbled on as I tinkered.