I came across this last weekend:
Basically Osu! is a Drumming game for the PC for which many popular (JPop) tunes are available. The principle is basically the same as for Guitar Hero, however with Osu! you can create your own fields and challenges!
For me it is a bit too much since I already suffer from mild RSI from now and then, but for all other out there: Try it! It is fun to do!
You can find Osu! here: