Capture The Flag
This mod really needs no introduction--it has become a standard multiplayer mode since its first appearance in Rise of the Triad. However, Capture the Flag's popularity really boomed after it appeared as a mod by Dave "Zoid" Kirsch for id Software's Quake. Players didn't need to download anything extra. They simply connected to a server with the mod already installed. Soon afterward, Threewave offered an expanded version, building upon Zoid's "classic" version and added downloadable custom maps and skins. This custom (Threewave CTF) version went on to become the template that shaped Capture the Flag in the Quake sequels and other first-person shooters.
Zoid was eventually hired by id Software to work on QuakeWorld and the CTF modes for Quake II and Quake III Arena. In 2000, Zoid worked as a senior programmer for Metroid Prime and Metroid Prime 2: Echoes for Nintendo. His latest gig was Valve's zombified first-person shooter, Left 4 Dead. As for Threewave, the group went pro and worked on the multiplayer portions of Soldier of Fortune II: Double Helix, Return to Castle Wolfenstein, Doom III: Resurrection of Evil, and even the recent Ghostbusters game for the Xbox 360 and PlayStation 3. As of December 2009, the company had closed its doors due to a lack of new contracts.