You can do it in most games, you just have to look around in the config file. I know there's an option in Quake 3, so anything using that engine should have it in the graphics config(ie: I've seen RTCW run on a plasma display, which is what you're probably shooting for. Just browse through your game files with notepad or wordpad(though don't set it to always open with either).
To get the number of pixels, whip out a calculator and multiply the standard height (ie: 1024x768 or 1600x1200) by 9/16.