GeeG - Technology Gadgets Food Toys Fun Games

Link: http://www.uberreview.com/2009/01/house-sitter-turns-random-stuff-on-and-off-to-deter-burglars.htm

A decent ides here- use one or more of these gadgets that activate at dusk and switch stuff on and off at random intervals. Put a few in different rooms and it would sure look like someone was home.