Hope this is the right place to post this but just got an email from GamersGate that they are having a Mac Games weekend with discount deals. I don't game on the Mac side (bootcamped) but might be of use for someone.
http://www.gamersgate.com/games?prio=relevance&q=macweekend&aff=ggnews
http://www.gamersgate.com/games?prio=relevance&q=macweekend&aff=ggnews