If building furniture worked the same way as constructing with Legos, a lot more people will be making their own home furniture. That is, if people were fine living in an entire house full of plastic furniture. At any rate, that's exactly what you get to do with the DIY Building Blocks, a set of blown-up construction bricks for putting together chairs, tables and cabinets for kids.
Just like Legos, the bricks consist of different plastic pieces with multiple connectors arranged in a grid throughout their bodies. Put them together by plugging the connectors and you can build functional sets of furniture that are just as useful as any crappy piece of plastic furniture you can get from the store.
Three sets of DIY Building Blocks are available: Lite, Amateur and Advance. The Lite version has enough bricks to let you build a single piece of furniture (a stool, a chair or a two-level stool); the Amateur gives you enough blocks for two items (e.g. a chair and a foot stool); the Advance provides pieces for up to three (such as a set with a desk, a chair and a cabinet).
The bricks aren't the same proportions or designs as Legos -- they get longer studs to make the connections sturdy, while sporting profiles that genuinely look like regular furniture. Each of the three sets come with instructions to build three types of furniture apiece, although you can always use the parts to get creative and build custom monstrosities.
The DIY Building Blocks Funiture are available from Thinkgeek, with prices starting at $99.99.