networking & communication
Since I was fairly scared of the the amount of C programming that I would not only have to do, but to learn, I decided to follow the AS220 tutorial which lead through the making of Neil's Hello Serial Bus board(s).

Hello.Serial.Bus with six nodes.
Milling and stuffing all the boards was relaxing and fun. And, I was able to peer into the code -- and actually understand some of it. In the future, I would like to fiddle with the C code to make the blinking more complex and fun.