If you don't already have Portal the following may be of interest.
To celebrate the launch of Steam for MAC, Portal is FREE for PC/MAC until May 24th. http://store.steampowered.com/freeportal/ (http://store.steampowered.com/freeportal/)
Portal is a physics challenge using gravity gun similar to the one in Half Life 2. Puzzles prevail so put your thinking cap on.
hey thanks a lot :D