@someguy201: I am sure that you already know this, but just to make sure, there is an incedibly useful keyboard shortcut for Windows 7 for this. In Vista, every time I wanted to start a game, I had to go to my desktop, properties, disable my second monitor, click OK several time, and on the other way around it was even worse (desktop, properties, enable, drag screen to left, change resolution, lose desktop icon placement etc.)
A massive pain. In Windows 7, use Windows Key + P to scroll through different monitor configurations. Massively convenient.