I saw a link to this on the Mach3 Yahoo Forum a few days back and finally got a chance to write it up. This also reminded me of a post I saw on hackaday using different technique.
The first technique extrudes cement in a fluid state in layers. The current results appear to be of mixed quality and they are clearly in a refinement mode. The use appears to be geared for artistic work rather than actual contruction. The whole thing is controlled via Mach3.
I saw this flat-pack inspired inspired playhouse over at inhabitots. Flat-pack is a form of a Ready-To-Assemble (RTA) product that ships in a flat state. The latest flat-pack craze is to see how efficiently you can pack the pieces into the raw sheet. The parts usually can be assembled without fasteners.
Gregg Flieshman has taken the look and assembly features to the extreme and produced some amazing designs. I was originally lured in by the playhouses, but some of his furniture is even more fantastic. The concept is perfectly suited to home router and laser folks because everything is done in the flat and there are no need to expensive, hard to get fasteners.
This is a handy Plug in for Google Sketchup. It slices a solid model so it can be cut on a laser cutter or router. It is called SketchUp SliceModeler. You can get it here. It costs EUR 10.