Epic Games is developing a new crowdsourced Unreal Tournament game that is open to contribution from anyone. The development process of this free-to-play game is very unusual, the developers are regularly releasing bits of code so fans can comment on the direction the game is taking.
The code is only available for people with an Unreal Engine but PC Gamer writes someone has compiled a pre-alpha build of the game that can be downloaded right now. There isn't much to see yet though, you can get a general sense of what the gameplay should be like but the levels are still greyboxed and a lot of areas of the game still need lots of work.
I've had a go and, despite the fact that I was jumping and hopping through greybox levels, I can confirm that it's definitely an Unreal Tournament they're making. Loading into it felt instantly familiar, and the frantic twitch gunplay is present even in this early version.
At this stage, though, it's not something I'm likely to spend much time with. It's an interesting curiosity—a window into the progress of an upcoming game—but not a fully-functioning shooter. Not yet.
If you want to check it out: download the latest build, extract it somewhere onto your computer, navigate to 'WindowsNoEditorUnrealTournamentBinariesWin64', and launch UnrealTournament.exe.