If you’re a Mac user who works with 3D applications — SketchUp in particular — you’ve probably figured out by now that there’s nothing equivalent to the Nvidia/ATI control panels on Windows for tweaking graphics driver settings, e.g. forcing the use of multisampling/antialiasing. Individual applications have to enable antialiasing on OS X, and many don’t, SketchUp included. Even so, SketchUp does have a hidden (and unsupported) option for enabling the feature:
defaults write com.google.sketchupfree8 "SketchUp.Preferences.AAMethod" -int 4
The last number is of course the number of samples; this tip is derived from this question on the SketchUp forums. This may not work on all Macs, and may make SketchUp less stable, but I’ve found it to work pretty well in practice.