Background input?

I was curious if there is a way to play using background input. If you don't know what I mean, I'll explain.
Some games let controller input continue going to the game when the window of the game isn't in focus. This could mean, for example, that you can be playing a game on one monitor with gamepad information going to the game while doing work on another monitor. A few examples of this I can think of are most emulators (notably, Dolphin), Minecraft (With the joypad mod), and TES Skyrim.