JRuby 0.9.2 was the first release to include a graphical IRB-based console. There are a number of ways to run it:

• Build the console jar yourself from source
  • ant jar-console
  • java -jar lib/jruby-console.jar
• Download the prebuilt console jar and run with java -jar
• Download the OS X application "SuperConsole 0.1" (based on JRuby) and install it however you wish
• Run the webstart version