There was soooo many cool projects to choose from, but here are my top few:
Conductive Paint by Bare Conductors
Ember (kitchen arduino hack for sous vitae)
Japanimo (3d object sensor)
Not quite an interface, but extra bonus:
Most Awesome 3-D printer!!! Prints resins, silicates, metals, enamels etc and CHOCOLATE! CHEESE! COOKIES! and therefore, more cool than any other 3-d printer.