>>106271613
Ten years ago I bought a pressure sensitive mat and put it under a small rug at the entrance to my cubicle at work. If someone stepped on the rug, the mat would detect it and turn on a rotating light and have a foam missile launcher turn to aim at the entrance way. It wouldn't launch anything, but it was enough to alert me that there was someone behind me and served as a distraction for them so I could lock my screen and turn around. Everyone, including my manager, thought it was funny.