Good news for indie game designers on OS X -- GarageGames has released version 1.7 of their Torque Game Builder, which allows programmers to create games for almost any platform from within an OS X interface. This latest release improves the editors for link points and collision polygons, as well as a new editor for vector objects and new t2dSceneObject methods. If you know what all that means, then you could probably program a better game than I could.
But the good news here is the one of the cheapest and best tools for game developers is now better than ever. Demos and trials of the tool are available on GarageGames' site, and licenses are as cheap as $100 for independent game developers. You've got the tools-- now go make us some great Mac games!