People at the 2012 NC Maker Faire were asking me if the documentation for my projects was online. (OK, one person asked, but that's enough to get me going.) So here's a description of my first project, the Reflex Circle, and how I built it.
My girlfriend's daughter likes to play a simple game at the arcade which consists of a ring of lights and a button. The lights come on sequentially and she has to hit a button at the right time to stop the light at the top of the circle. So I built a version of that. Here's a video of of me playing it: