Call of Duty - Call of Duty is a first-person and third-person shooter series by Infinity Ward.

Steam Charts - An ongoing analysis of Steam's concurrent players.

Quake - Quake is a series of first-person shooter video games released by id Software.

Steam Database - This tool was made to give better insight into the applications that Steam has in its absolutely huge database.

Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.

Steam Spy - Steam Spy is Steam stats service based on Web API provided by Valve and cool idea of Kyle Orland...