I have a MakerBot Cupcake 3D printer. Although the quality of prints you can get out of that machine are not the absolute best, it does provide a platform upon which much 3D printing experimentation can occur.
One of the things I have played with is the fasteners on the machine. There are lot of screws and nuts that must be put together in order to assemble the printer. I thought it would be a good idea to use a quick clip to assemble the robot, so I created one. it is out on thingiverse here: http://www.thingiverse.com/thing:5493
I have completely removed all of the screws from my MakerBot Cupcake, and replaced them with this clip. The box went together quickly and easily, and comes apart the same.
It seems to be strong enough in its current form to do the job of connecting the individual panels. I found it quite easy to do the construction, and it went along much faster than when I was using the screws.