Games Like DefinitionNine's Audio Endpoint Switcher

DefinitionNine's Audio Endpoint Switcher provides a Windows Task Tray icon that lets you switch your audio output device with one click. You can call it up via a hotkey or by clicking it's icon in Windows' system tray. The intent is to make it easier or quicker to switch outputs compared to going to the Sound Properties page. It is a utility program and not a game.

Disclaimer: It does not function as a game overlay, sadly. If your game is running in full screen mode then invoking this tool will bring the Windows desktop to the fore.