Contour Crafting, a 3D printing (or additive manufacturing) method being developed in California, takes the MakerBot and embiggens it to build things like houses. Just replace the plastic with a concrete slurry, and actuate a couple of trowel-like devices around the feed. Layer by layer, you can create a building.
The technology would completely alter the construction industry, reducing human factors to loading concrete and installing doors, windows, and other fiddly bits. They’re even working on how to incorporate rebar and structural steel in the midst of the process, all the way up to really ambitious (and unwise) things like wiring and plumbing.
The whole thing would break down and load on a flat bed trailer, or for smaller buildings, might even Transformer into place like a mega-crane. It’s being explored for everything from low-income housing to moon base construction.