One of my most popular projects has been the etched Altoids tins that I made for the Steampunk Bible article I wrote. For years I've carried one in my bag that I've used for various medications and vitamin pills when traveling. I had cut up one of those typical SMTWTFS pill boxes to make the dividers and while it worked well enough it was a royal pain to get the pills out with my no-so-slender fingers.
I took to carrying tweezers in my bag to for this very purpose. Of course the TSA is of the opinion that 00 Non-Magnet Stainless Steel Tweezers are a threat to the flying public. :-/
Then a friend suggested that I print dividers for the tins on my RepRap 3D printer. Brilliant! and I can incorporate a pair of tweezers right into the design!
I am still searching for the right tool for designing things to be printed. Autodesk's 123D is currently the one I use most but it is less than complete and crashes a lot (though not nearly as much as it used too!) But it was up to this fairly simple task.
I worked up a design for the dividers and tweezers and then used the tweezers as a "tool" to cut a place for them to rest in the top of the dividers.
AutoDesk 123D File: Tin divder and tweezers
STL File: Divider ans Tweezers
If you'd like to make your own tweezers and dividers the files are linked above as well as on Thingiverse.
I printed them in clear ABS, which is currently my favorite material. It sticks well to the glass build plate and has pretty good internal adhesion. I am currently building a heated enclosure for my printer build area and I'm hoping this will further improve the print quality.
The first iteration was too small, I am still calibrating my designs for shrinkage. However 123D makes scaling the part up by a couple of percent relatively trivial and the current design fits into the typical Altoids tin quite tightly.