Lots of traffic comes here looking for Cider information – Cider is a windows emulation technology for Mac, a cousin of Cedega on Linux. There are many official game ports from EA, Ubisoft and indies that use Cider ‘wrappers’ to make their games work on OS X. A community has sprouted up that seeks to port more and more games to OS X – due to the lack of official developer/publisher support of the Mac.
This produces a constant stream of new releases (many are games that time has forgotten – something that has its own unique charm). If you want to learn more, head over to the Porting Team website and register for the forum (my handle is Scary Perry).
Maybe someday the ease with which normal people are porting Windows/DOS games to OS X will encourage game developers to support the Mac.