Excessive dawn (edawn) is a free Quake 3 Arena mod, with numerous improvements, both client and server side. Biggest feature is the fact you can tweak almost every single aspect of the game, from weapon behaviour to making your own mini gametypes. All powered by a tweaked netcode. Mod works with any Quake 3 version that uses QVM (quake virtual machine): vanilla Q3 Arena, open arena, ioquake3, whatever executable you might make yourselves..
This is an early version of the Official Quake Live mappack for Q3. How ever most of them came from q3, but there are some new one, and of course the have better graphics (if ur a graphicwhore).