I think I've seen this in the news before, but I liked it so much I thought I'd add it in.
This is a device that detects when a radial saw is about to cut your finger and instantly stops the saw. The demo (on a hot dog) is amazing.
SawStop LLC was formed to make active devices for woodworking equipment.
It would be great to work for a place like that and feel really good about what you are doing, instead of say, helping exploit low paid Chinese workers while helping to polute the Chinese countryside all to create a lower cost product.