For those of you who have long since moved on from Quake II and want to relive some of those memory's of your youth. or those of you that have been looking to play Quake II but not have to put any money into it, Here is the solution!!
TastySpleen's Quake II Starter Kit

If you just want the basic game without the Q2PRO, download the Quake2 Demo
Then the Quake2 3.20 Patch
Make Sure you Install both to the same folder or they wont work.
The two Files will give you the ability to play OnLine!