I actually read this paper a little while ago, but haven't had time to post anything about it until now. The group of George Whitesides (who seems to have research touching on everything under the sun) has recently published a paper on making 3D microfluidics devices using paper and double sided tape: http://www.pnas.org/content/early/2008/12/08/0810903105.abstract
For those who don't know, microfluidics is the art of pushing tiny amounts of fluid around and stuff with it. This is a good thing because you can do lots of interesting chemical reactions and analytical type stuff at a micro scale very cheaply that would be otherwise really expensive (as well as a whole host of other things). This is useful for making cheap disposable tests for developing countries, as well as carrying out many different analyses using material from one sample.
From my understanding, most of the research in this area involved manufacture on silicon chips and the incorporation of pumps and gates and all kinds of minituarized gates and mechanical things. There had also been stuff published previously on using paper for this kind of thing, however most of the devices were 2-dimensional, or could only take advantage of one layer of paper. Whitesides and coworkers decided to investigate the possibility of making paper devices 3-dimensional using double sided tape and a paper paste to create channels in the paper. If you can access it, the paper is actually really interesting and not severely technical. There are also a bunch of news articles floating around the web on this, here is one:
In the paper, they demonstrated that they could make these microfluidic devices by hand and carry out simultaneous analyses on different samples, just by dipping different corners of the device into different fluids.