I had this idea last night. If your home is being invaded, try setting off your car alarm as a pseudo-home alarm. May be enough to give the bastards pause.
Actually, not a bad idea at all. I do a version of that with a modern twist on the lift bracket of the garage door using chimes. I use a large 1/4 inch spike through the sides of the garage door panels and the door frame at night and one on each side if going out of town. Now ya' got me thinking that for the front and sliding glass doors.String some wire and hang beer cans like in the zombie flicks.