Out of the box, Quake 3 Arena plays great on a Mac, that is if you don't mind rebooting into OS 9 to play it. Well, I did, and do, mind. After starting to play the excellent game Medal of Honor, which is based on the Q3A engine, and runs under OS X, I finally got around to putting some real effort into making Q3A itself run under OS X. I had tried before to apply the 1.32 OS X patch, but ran into problems running the game - I ran into those same problems again on this go-round, but laboriously worked my way through them by visiting several support sites and forums.

I've decided to document the steps here for everyone's benefit. Note that these steps worked for me on the Quake 3 Arena, Gold edition, under OS X Panther. Your mileage may vary.

1. Move your Q3A install folder to the Applications (system, not user, domain) directory. By default, it installs to the "root" directory of your HD, as shown by Finder. I believe this is because it was shipped as an OS 9 app.
2. Rename the install directory something unique. I named mine "Quake 3 Gold".
3. Install the 1.32 point release. The patch is available from a number of download sites. I got mine from Planet Quake. Run the installer, which will put the point release in a "Quake3" folder under Applications. I renamed this folder to "Quake OS X", but you don't have to.
4. Copy the PAK0.PK3 file. Copy the file from the "baseq3" directory of the original install (the one you just moved) to the baseq3 of the point release's Quake3 directory.
5. Run the "Quake3 10.2 G4" app, and frag away. If everything is set up correctly, upon double-clicking the icon, you'll be immediately greeted with the id logo in a small window, followed by a switch to full-screen Quake. Rock on!

I have to admit the multiplayer mode of this particular release crashes on my machine. I haven't bothered with multiplayer Quake in a long time, so it wasn't a real disappointment. Therefore, I haven't researched how to fix this particular problem. Perhaps it's just my setup.