Ahhh, how could I forget? Worms and Zoop! two excellent and very quick games. Also Airburst, Cro-Mag Rally, the Zork series, MacChess and Pro Pinball: The Web. Airburst and Cro-Mag are available for OSX, don't know about the rest. But this topic is about games first and foremost, not the operating system, right?