Personal Fabrication Machines. Not expensive/rare 3D printers though, there are over 1MM personal paper cutting machines like the CriCut and CraftRobo that have already been sold. They need good software to drive them. I think there is a tremendous market opportunity here and would be interested in any feedback people have.
There are some slides fleshing the concept out on this page:
There are some slides fleshing the concept out on this page:
http://ycombinator-w10-cofounder-search.tumblr.com/
What do you think?