Have a look at this screenshot:
A nice warehouse
TeamFortress2, right? Well WRONG ;) It is actually a screenshot from one of the maps from the upcoming War§ow 0.55 release!
War§ow is a open-source game based on the updated Quake2 engine QFusion, and has already seen some quite successful previous releases. They focus on a fast, e-sports style game play and their general art direction is a pretty nice cell-shaded comic world.
Lately their their style has been for sure party influenced by TeamFortress2 however, which at least in my opinion is not a bad thing :) For a whole bunch of other screenshots and an update on what else you can expect from the new version, check out their newest blog post here. Overall there will be some pretty nice improvements, and probably a significant performance increase with VBO integration into the engine.
But maybe most interestingly, they will also include a new game play mode, Capture the Flag: Tactics. And guess what? It will be a class based team CTF, with turrets and ammo dispensers. Sounds familiar right? :p
Say Hello to Mr. Turret
Sadly I have to mention though that the art content of War§ow is completely unfree, and its development team shows a general lack of interest in the idea of FOSS... Yes the engine source code is available, but probably only because it is GPL and therefore has to be.
Second lesson for today, kids: GPL is good, mkay?