Modular Combat is a role-playing shooter based in the Half-Life universe. There are over 50 modules that can be upgraded at any level, in any combination. Modules give combatants amazing abilities such as flying, teleporting, spawning minions, and shooting flechettes or energy balls.
If you have already installed v1.75 and only intend to play on the official servers, then get this and unzip it to your "SourceMods" directory. Otherwise, get the full version and install it.