DoThisNow for Mac

From Radical Breeze:

DoThisNow can easily setup your computer to run repetative, time critical or simply mundane tasks for you.
You can setup an action to occur every minute, or only once five years from now.
Schedule your computer to perform any of the following tasks:

• Launch any application or file.
• Display a customized message.
• Delete any file (if it exists).
• Delete the contents of any folder.
• Run an AppleScript.
• Optimize your system.
• and even Empty the trash.