A direct "like for like" replacement for the GameSpy MasterServer, and supports a huge number of games.
333networks is the official MasterServer for several games companies, and can be self-hosted, or use the main Master, or both.
Most alternatives require that players and admin install and run a 3rd party client which may conflict with other clients (especially Steam), and sign-up to a web site.
333networks MasterServer uses the original system built into the games, so people see the server lists where they originally appeared.
Players and server admin only need to change some lines in their game configuration files.
Hard-coded games can be updated by the game authors upon request, or redirecting the GameSpy URL to 333networks in a modified HOSTS file.... More Info »
Still in active development and many games have been verified to work, including;
Duke Nukem Forever
Soldier of Fortune: Retail
Star Trek: Bridge Commander
Unreal Tournament Demo
Wheel of Time
Many more games are potentially supported, but have yet to be tested.
Contact 333networks at the forum, Facebook or IRC for help resurecting your old games