Print your own analog computer
The plan is to compile function definition to openSCAD programs that can be printed on 3D printer to produce the cogwheels for implementing the function.
Market: Geek parents everywhere; science museum shops etc.
Status: We have code to produce cogwheels. Haven't done the printing yet. The compiler is TBD. Looking for people to continue with the project.
See the videos here: http://www.metafilter.com/89205/Basic-Mechanics-in-Fire-Control-Computers
People involved: Ohad, Ehud