This is pretty impressive --of course there are already lots of ways to automate actions on your Mac, and odds are that you may have messed around with scripting or Automator more than once before. But Sikuli is a new app that makes automating as simple as taking screenshots. Instead of programming actions, all you have to do is put screenshots of the particular UI items that you want to automate in a list, and then the app will use visual cues to do whatever you want it to do. Not only does it make things much easier when actually writing scripts, but it also gives you countless options in terms of automation -- the app can automate any app that has a graphical user interface, because all it has to do is recognize that GUI on your screen. That includes web apps, too -- like I said, the possibilities are endless.
And since it's developed with Jython, you Python experts can insert any Python code that you like in the scripts as well. The whole thing is an MIT project, so it's available for free across all platforms, including OS X, Windows, and Linux. If you've been looking for an automator that'll do any rote task for you, give Sikuli a try.