Was watching the Gadget Show tonight (here in the UK) and saw a feature where they were showing a beanie hat with this "D3O" putty/gel material which is soft when handled but on impact becomes hard. It stopped a hammer blow to the "head" (well, they used a melon).
http://www.streetgadgets.com/subcat/252/RibCap.htm
Here is the website for the D3O material itself:
http://www.d3o.com/
Could be useful in gloves, plastrons, bibs etc?


