I'm sure that this has a) already been posted before and b) is easy, but can someone please tell me how to run a program in the background? Basically what I want is to have a program that will run in the background and when I press, say, the 8 key, will open up a window, or perform a command. Basically, what I want to do is come up with a way to assign hotkeys, but to take it one step further and allow allow someone pressing a series of keys to cause an effect.

Hope that makes sense.
Any help that you can give is greatly appreciated.