Tribes Revengeance is a free and open source community repack of game Tribes: Vengeance. Developed by Irrational Games and released in 2004 this is the 3rd game in the Tribes series. Tribes is known as an FPSZ or a First Person Shooter that focuses on verticality and movement.
Tribes Revengeance is a community driven open source version of the original game. Most notable features include an updated server browser, visual improvements, bug fixes and the ability to be played on modern hardware. This version of the game can be obtained from https://downloads.tribesrevengeance.net/TribesVengeance.zip
Tribes is referred to as an FPS-Z, a first person shooter that runs quite heavily on the Z axis. That means that movement is just as important as actually shooting is. In Tribes, you're given access to a jetpack, as well as a ski button. Skiing down a hill helps build speed, and your jetpack helps lift you up into the air, these mechanics working together allow you to fly up and around at high speeds and make it a challenge for your opponent to hit you.
The game also features a variety of vehicles, an array of weapons, and different armor classes that you can choose from.
(Ripped from rowdy's Jewelbox post ^)