Catch laptop thieves with Prey Project
Came across a neat project recently, open source with GPLv3: http://preyproject.com/
Basically, it's a little piece of software that connects to a server and lets you know where the laptop is if a thief steals it. It's open source so you can set up your own prey server and have the device connect to that.
Prey is for Windows, Mac, and Linux. Free signup is required for the use of their server.