You've probably heard of programmed lights on timers that make it appear that someone is at home even if you're away on vacation or working late.  Well, now there are a number of outfits selling CDs or downloadable MP3s full of "burglar deterrent sounds."

The idea is that you can leave these sounds playing while you're gone, and it's supposed to fool a potential thief into believing someone is at home, thus encouraging them to move on to an easier target. 

I suppose it's somewhat logical (I could see it working in a dorm or apartment setting) but it seems like a silly thing to pay for.  Would you actually want to leave your stereo on and running (and wasting power) while you were away from home for a week?  Or even a work day? 

Now if the home automation pros come up with a device that plays a cd only when motion is detected in the yard (such as how motion-sensing lights work), that might be more practical.  But then your neighbors might get ticked when they come over to borrow flour (does anyone do that any more?), hear you rummaging around inside, but then are left standing on the porch when no one answers the door.