Google Earth Flight Simulator
The good folks at Google have included a Flight Simulator in the latest version of Google Earth, version 4.2. To access the game just hit CTRL-ALT-A (Command+Option+A on the Mac) and you get a dialog box allowing you to choose from two types of aircraft - an F-16 or a SR-22, and choose from one of several airports.
There are two types of planes, an F16 and a SR22. Of course I prefer the F16 and the New York area airport looks fairly realistic. I found another fun way to waste valuable time at work. F16 is pretty cool.
The controls can be found here - Google Flight Simulator Controls.