I wrote a Q3 mod that we used to play here at the office after hours.
The mod:
health == 999
player movement speed increased quite a bit.
Rockets flew ultra fast (almost like a rocket rail gun) and fired at an increased rate. 999 rocket ammo.
Rocket splash damage increased dramatically.
Rockets caused NO damage to the person that fired it...so rocket jumping was crazy because of the massive rocket damage...you would literally fly across the map.
You could shoot rockets out of the sky (mostly only happened by luck).
Rail bounced 4 times. 999 rail ammo. Rate increased. Damage increased.
Plasma flew ULTRA slow (almost not at all...well at first they didn't move at all and were used like mines, but then we ended up with everyone just mining the map). Plasma damage == instant death. Only 8 plasma ammo per person per round. You can shoot plasma out of the sky (but watch the splash damage).
Shotgun...LOL...shotgun shot 4 spread bouncing rails plus increased ammount of shotgun pellets, plus massively increased rate of fire...only 25 ammo count which was spent just about instantaneously...this weapon, when fired, basically spit out a mass of mayhem that decimated everything in it's path...we often agreed to not use this weapon, as it was rather rediculous.
Also made a handfull of maps specifically designed to be played with this mod. Map names: be quietnoob, fux0rd, omfg, pwned, blarg, eek, rox0rz, umph, wtf, and hammer
Olympiad, a map I made for paintball, was actually a conversion map I made for this mod.
Only the weapons mentioned above were available.
Oh...and I changed all the game's messages...so when someone killed you with a rail for instance it said: <killer's name> shoved a rail up <dead person's name>'s a$$...and crazy stuff like that.
you can download the mod the source, the maps, the bat file to run the mod, and whatever else, here:
http://www.logictechnologies.com/keith/stuff/q3mod