Here's a device category that's been left largely untapped: the doorbell. The Recordable Reminder Doorbell uses a motion sensor to either sound a conventional chime or play back your own recorded greeting. Movement within six to 12 feet of this voluptuously-shaped device triggers your choice of chime or greets. Say hello or tell 'em to go away. Now if they could just make one where visitors can also leave you a message. Running on three AA batteries, it's $15 on the web.