Looking for some retro fun? Head over to sc2.sourceforge.net and download yourself the reincarnated classic Star Control 2, now known as The Ur-Quan Masters. The source code for the original early-90s game was opened, which has allowed it to be ported to various current operating systems — including OS X.
If you have the bandwidth and patience, be sure to download the music and voice packs too, so you get the full game experience. What are you waiting for? Help free the Earth and destroy the thrall forces of Ur-Quan for good! ;)