When I was giving presentations about assistive tech for my thesis, I had one of those toy grabber/Waldos, which just used a soft grip--it was made for kids--and it also made a variaty of science fiction sounds. Adults loved it. I should get another one.
One of my major tips: check out kids's toys, they tend to make use of really advanced technology, are easy to learn and use, and are often pretty cheap. I used to bring things I found to folks in the MIT Media Lab and they would just go nuts.