A freeware version of Quake: Team Fortress built off the eZQuake client.
"For those who don't know, zelTF is a stand alone QuakeWorld Team Fortress compilation and installer. Meaning that this amazing game is now available to anyone, ready to go with the click of a button, 100% free of charge. The website is still very much under construction, though the zelTF forum is up, check it out.
* ezQuake 1.9 alpha (zelTF build)
* Maps including textures, lighting and loc files
* Various Configs
o Grenade timer
o Audio notifications
o Communication binds
o Sniper zoom
o Quick weapon change
* Team Fortress scoreboard
* High resolution gfx and models
* Advanced and easily edited configs and key bindings
* High quality sound effects"
FYI! Set your Graphics option to - "Faithful", for it to look like the old reliable Quake