Universal 'windowizer'?
 

You know how some games come with the option to play in 'window mode' (not full screen)? I wish more games were capable of doing that. I'd really love a program that makes ANY game run in window mode.

Is this possible? does anybody know of a program that does this? Or maybe Windows has a built in keystroke that automatically does that?

It seems like it would be a pretty simple concept..but I know nothing about how that kind of stuff is programed :D

Thanks!