Gamers: Download Valve software's Portal, for FREE, for Windows OR MACINTOSH
 

http://store.steampowered.com/freeportal/
To celebrate Valve's Steam platform release for Macintosh, they are giving away copies of Portal. If you've never played portal, you really need to. It's a short game from start to finish (a couple hours of gameplay, maybe?) but it's very innovative and a ton of fun. It really makes you exercise the spatial part of your brain.