Room Defender $35

See the Room Defender at New Scientist No More Socks

Sometimes gadgets can be just plain silly. Protecting a room for intruders is one thing, but pelting them with foam disks might be going a little far. Intended for the kid who wants to maintain privacy in his or her personal space, the Room Defender acts as a silent sentry, standing guard until it detects motion. It comes to life dealing an barrage of ammo. I must admit to finding this slightly clever, with more than a slight nod to Aliens. It might be a harmless tool for deterring pets from eating house plants or just as a curiosity to surprise guests at an evening dinner party (after all, nothing improves a trip to the bathroom like being bombarded with little disks. A tripod mount makes it easy to put this gadget almost anywhere in the house.