Scare away trouble with your very own junkyard dog—minus the mess. This model's sensor works through doors and windows to detect motion in a range of 30 feet, and responds with a realistic barking sound. You'd be surprised how many burglars retreat at the sound of a vicious canine inside. Just make sure the joke's not on you: large glass panes in entry doors create easy, breakable access to inside locks and handles, and will allow burglars to see there's no threat of an animal inside.
About $90, Hammacher Schlemmer