I’ve been following the development of 0 A.D. with great interest over the past few years. It started as a full-replacement mod for Age of Empires II, which I played extensively in high school, and developed into a full-fledged open source indie RTS. They’ve made some remarkable progress in the past few months, and I was very happy to finally get the latest alpha release to work on Mac OS X (their Mac support has been shaky or non-existent in the past).
The instructions on their OSX build website are quite good, with the exception of the fact that (at least with this version) you have to manually set up some dynamic libraries. This process is described in a bug report in their Trac system. With the links established, the latest alpha (version 8 “Haxāmaniš”) works (albeit without sound) on my iMac. W00t! Kudos to the team, and I await further development with eager anticipation.