impact-sensitive body armour
There was a thread around here a few weeks back about futuristic armour that could distribute the energy of an impact.
I just watched an article on TV about this cool substance they're putting in sports outfits. It was called D3O.
I watched this guy take a hand-sized lump - it looks and behaves exactly like plasticine - and mold it easily into an amorphous blob. He then picked up a hammer and whammed it several times, and it hardly distorted at all!
Sci-fi eat yer heart out!