I know we dont have many mac os users in our community but would like to present new way to play on mac. Its called Wineskin
Its not perfect but seems to be better solution. I havent installed yet it using Wineskin, just copied already installed GCCG, so dont know if this option works. But if you have running program from Windows, its enough to copy it. So far i noticed two small "problems". Writing symbols of regions works good (just shift+control and letter key) but if you want to use symbols of sites have to use combination shift+alt+command key+letter key. The same way to write regions from the map during the game - ctrl+alt+command key and click on the region.
I dont know why but to run GCCG using Wineskin have to click 2 times on the icon. First, wait a moment, and double click again.
If you have any question, ask me, will try to help.UPDATE 27.10.2013
Dear players. Finally i had some time and made working copy for MacOS. Its clean, without any users, so when run it, have to create account (like using normal GCCG). Its very easy. You have to download Wineskin(nothing more, just to have it on your computer) and rar archive (link below). Unpack it and its ready to use MacOS-GCCG Wineskin
This also is version 0.9.6.3 and includes all normal sets (The Wizards - > The Balrog). I skipped Dream Cards because it makes file much bigger. But you can download them via SVN and put inside this copy.
If somebody has any problem let me know, will try to solve it. Also let me know if it works (to make me sure everything is ok with this copy). I had some small problems (user and his password) with first version but later they didnt appear.