How to build a laser security system (it's easy!)

Yes, folks, I'm on vacation. And so should you be. There's really no reason to be working between Christmas and New Year's unless you work at my local liquor store. In which case you need only come in for the 15 minutes necessary for me to pull up, grab more Jameson, and leave. Since you're on vacation, like me, you've probably got some time on your hands. Here's a nice project to do with the kids. I'm sure you've got a circuit board and a LM741 microchip lying around since you're a security guy and all.