At the moment, you can buy 2 games for 12€ or 6 games for 30€ for your Mac at Get Games .
The games come as download versions. The offer is only available until monday, the 28th of january.
The following Games are included:
Call of Duty 4 (31,99€)
Call of Duty 2 (16,99€)
Duke Nukem Forever (15,99€)
Doom 3 Mac (7,99€)
Quake 4 mac (15,99€)
Rage – Campaign Edition Mac (31,99€)
If you already need Call of Duty 4, this one seems to be a nice offer.