TQ is a sidescrolling multiplayer Q3 mod, encompassing three maps. Think of it as a map pack on its side. You can play with bots or players, in ffa or teamplay.
They have a server running at 188.8.131.52 presently.
games.alphacomplex.com:27961 is also running a server.
Use your strafe keys to move, mouse to aim. Just like Quake3!
Put the zip into your quake directory and unzip with folders enabled. This will put the contents into quake3\tq. Now you can select TargetQuake when you click "mods" in Quake3, or you can type: quake3 +sv_pure 0 +set fs_game tq +map tqdm1 (or tqdm2, or tqdm3).