Xonotic is absolutely amazing multiplayer. Extremely competitive and fast paced. There isn't a large number of online players but I can always find a Deathmatch

Xonotic is absolutely amazing multiplayer. Extremely competitive and fast paced. There isn't a large number of online players but I can always find a Deathmatch or Team Deathmatch to burn 15 minutes on. The weapons are excellent, like a mix of Quake and Unreal Tournament. I play it almost every day. Edit: if you download it and install it, be aware that there's a script buried in 'misc/tools/rsync-updater' that updates to the latest autobuild. The last official release, 0.8.2, is really old.