A material that can ... transport particles and assemble shapes.

From the DARPA press release:

Professor David R. Liu’s Harvard team is relying on DNA base pairing as a sort of molecular Velcro to program the assembly or disassembly of “smart” materials. At the Massachusetts Institute of Technology, Professor Daniela Rus has created an innovative computational origami of two- and three-dimensional functional structures, through the “folding” of matter.

http://www.darpa.mil/news/2009/ProgrMatter.pdf

In the future perhaps downloadable design will become a reality for all worldy objects. Perhaps you could download the latest shoe design into your pool of matter and see it assembled before your own eyes! Imagine if you could download physical objects from the internet like food or drink – some crazy possibilities.

I guess we are a step closer now to all being turned into grey goo…