Home Surveillance Equipment
Private home security cameras used to be the domain of the very rich (or very paranoid), but they're pretty common these days, and you don't even need a professional to install them. Just mount a few (fairly inexpensive) wireless cameras in strategic locations, connect them to your home computer network, and voila -- you have your very own surveillance system.
You can watch the camera feed from anywhere with Internet access -- all you have to do is enter an IP address into any Web browser, even the one on your cell phone. It's pretty simple, but if all this sounds like too much trouble, you can always install a dummy camera (complete with blinking LED light) in a prominent spot -- who knows, it could be enough to keep intruders at bay.