Self-Healing Composites
Nick pointed us to this AP story about self-healing composites, fibrous materials with integrated, fungible glue capsules - so that each stress which breaks fibers also breaks the glue capsules to repair those fibers. Very cool stuff, especially if they could make the glue set fast enough to repair in "real time". The Washington Post has another article about the same thing with a bit more detail.
What happens when you come to demolish the structure? Is this going to be like throwing away a boomerang?