Looks like Who has jumped on this, so I thought I would share again. Fun and free shooter, was originally a Q3 mod but now stand-alone. Updated game engine, most console commands, bindings and scripting the same as ET.
Urban Terror - free to play shooter, mainly TDM, CTF, LMS
Originally was a Q3 mod, but now available standalone with updated engine (ioquake3) similar to etlegacy. Used to play it alot prior to RTCW and ET