Kids are loving this game called Guitar Hero, where you play along with famous songs.
Only problem for us PC folks is that it's only available for Game Consoles (PS2,etc.)
Thankfully, if you're interested in such things, there are some free clones for the PC (Windows, linux, mac):
Frets On Fire: http://louhi.kempele.fi/~skyostil/uv/fretsonfire/
Freetar Hero: http://antonstruyk.com/freetar/index.html
For more discussion: http://www.kotaku.com/gaming/harmonix/