A simple stopwatch with logging and a running average.
I wrote this when I couldn't find a simple stopwatch app or website (that worked cleanly on my phone) to track my average times for Rubik's Cube solving (I'm down to 1 minutes and 15 seconds now).
Feel free to use it for your needs as you will.
-Mark
P.S.: I've since found http://www.cubetimer.com/ and I'm now noting that here.