Gamma Panel is a little & handy application that lets you adjust brightness, contrast and gamma settings in real-time. Thanks to its hot-key feature, you don't even have to leave the game you're playing! The program works pretty similar to Color profiles in PowerStrip but is completely free and much smaller in terms of system load and memory usage.

The program is pretty simple - it just sits on the taskbar and does its job. You can apply profiles in 2 ways: by pressing assigned hot-key combination or by selecting the entry from the popup menu. The last selected color profile is automatically applied on the next program run.