rb-appscript is a free and open source Apple event bridge for the Ruby scripting language. rb-appscript is closely based on the Python appscript (py-appscript) bridge.
Take a look at the rb-appscript-0.3.0 folder for full documentation and sample scripts.
The included .pkgs will install rb-appscript for Apple-installed Ruby 1.8.x on MacOS X 10.4.x PPC and i386.