A while back merlyn posted a link to a fascinating article on HyperSound (unfortunately now it's for pay), a way to project sound in a beam a bit the way a laser is projected compared to natural light.
The article mentions it being at Radio Shack. I want to buy an HSS emitter, preferably the component. I couldn't find anything from Radio Shack's website. The parent company only sells largish ugly things (that I could find). Does anyone have any leads on this? I'd really like to have one.