While I wait for a little cheap-o stepper motor to arrive for the next project, I thought I'd share with you something Arduino-related that I just got my hands on - it's the MintDuino from MakerShed... and it's totally cool... and really fun to build.
Everything you see there on that little breadboard fits in that tin. The breadboard actually folds up - the power/GND columns fold back and then up to snap into place, making it fit nicely in the tin, too. It took me about 20 minutes to assemble using the instructions over at MakerShed, and it's not as "user friendly" as a real Arduino due to the lack of labeling... but that, to me, is where the fun begins.
I took the MintDuino and began comparing it to the Uno... I used the circuit tracing that you can see on the surface (front and back) of the Uno and was able to determine which pins are which on the Atmel chip. If you want to gain a little better understanding of the Uno's circuitboard, build your own MintDuino and things start to click. (Not everything... I'm still learning and figuring things out - there's a lot more I don't know than what I do know...)