Gizmodo reported on a machine that can actually "print" (read fabricate) a house from detailed drawings. According to the source article on New Scientist:
"It takes instructions directly from an architect's computerised drawings and then squirts successive layers of concrete on top of one other to build up vertical walls and domed roofs."
The machine has been tested with a cement mix, but the inventor thinks that the machine could work easily as well with a mud and straw mixture for consumers desiring a little more third-world construction material.
The coolest thing about the machines is that it can operate around-the-clock with very little supervision (and certainly no breaks, late starts, or early end times). The first prototype house is slated to be constructed in 2005, and designers, according to the article, think that there may be the potential to use this machine to make curved walls and other architectural marvels that are otherwise very difficult with conventional techniques.