We get a lot of Kickstarter project submissions that are neat or okay, but rarely are they as mind-blowing as Sabertron. A foam sword and an electronic scoring system with multiple game modes combine to create Sabertron. Using what they call "extraordinarily complicated scientific engineering type stuff," Sabertron can detect between a block and a body hit.
The team from Level Up has a great intro video which I think is key to any crowdfunded project. They are very close to meeting their goal, and it looks like they will be expanding their product line in the future to include "smart" shields and armor.