Do you have Fraps installed?
Like many of you (?) know Fraps is a program that shows the live framerate during 3d apps, like games (and some movies as well). I've had it for years (starts with windows) and I couldn't live with out it. It's like a speedo-meter in a car. Especially it's useful when I get a new game and configure the graphics settings.
Also with fraps you can capture screenshots any time during a game and also capture videos.
If you don't have it and you're a gamer, get it now.