Scheduled Shutdown on OS X
I found a mac app (actually two) on the App Store, that allow you to set a timer for when you want your mac to shutdown, restart, sleep or logout. I thought this would be an easy app to build so I attempted my own.

I considered posting the instructions on how to write this app, but it is really simple to implement. In fact, Apple provide you with the most important part of the code.
So instead I am just going to open source the code for this app, and let you lol at the simplicity.
If you are a good (or just better then me) interface designer, feel free to modify the interface into something nicer and get it onto the App Store as a free download.
I've also made available an universal binary of the app. Enjoy.