This is a project to build a vending machine that 'vends' all the 3D-printable things on thingiverse (http://www.thingiverse.com).
There are three main parts to this project:  
1:  A spider that grabs things from thingiverse, generates an info file on them, downloads images and .stl files related to the 
thing, and uses skeinforge to generate gcode for a makerbot.
2:  A user interface that displays images and information about the things and lets users search and navigate the library of things
3:  A hardware interface to the vending machine and the makerbot.  It talks to the makerbot via the control program replicatorG (http://replicat.org/), controlled with applescripts, and it talks to the vending machine hardware over a serial port.

This basic vending machine concept goes like this:
There's a UI on the vending machine that lets a user browse the parts that the machine vends.  When a user selects a part and hits
"build," the UI asks the user for their name.  Even small, simple parts take 20 minutes to build, so the machine will store the part 
for the user under their name, and allow the user to come back, identify herself, and retreive her part.  Once the user enters her name, 
the program tells the makerbot to start printing.  The vending machine itself has a motorized carousel with six bins, each of which can 
store a printed part.  When the makerbot finishes, the program commands the carousel to rotate to an empty bin, and the makerbot's 
automatic build platform pushes the part from the makerbot into the bin, leaving the makerbot ready to build the next part.  

If a user returns to pick up her part, the program will ask for her name, look up which carousel bin corresponds to that name, rotate 
the carousel so that that bin is in front of an access door, and then unlock the access door to allow the user to retrieve the part.


This is basic demonstration of a concept, and there's plenty of work that can be done to make the code and machine more robust and
functional.  3D printers aren't fast or robust enough, currently, to make a public-use vending machine viable, but they'll be there in 
about two years.