You need ssh access to your Apple TV. Drop the plug-in into /System/Library/CoreServices/Finder.app and from there into Contents/PlugIns. You then have to kill and restart Finder.app. (Do a ps -x to find the process id).
What the plug-in does: I wrote it as a proof of concept for testing running command-line utilities through the Apple TV interface. “Weather” gives you a weather report for Denver. (You can modify the zip code in the plug-in bundle in Contents/Resources/Weather.perl.) “Time” tells you the time using /bin/date. There’s also a “Foolery” option that simply displays a static string. Finally, you can “Quit” from the Apple TV UI. (Not very useful unless you’re hacking.)
Use at your own risk. Give feedback. Don’t sue. How-to hopefully to follow.
Update: Just for the hell of it, I also wrote up an appliance that allows you to run any perl script you stick into your /Users/frontrow/perlbin folder. Feel free to test it: