In search of better dental hygiene, my wife and I got the "Waterpik Complete Care Water Flosser Power Toothbrush Combo". It has an elaborate storage compartment for all the various squirting heads of the "water flosser", but no place to put the two toothbrush heads it came with. I modeled and 3D printed a holder for the toothbrush heads, which we attached to the wall.
Step 1: Print the Holder
This is really the only step. In the picture, my prototype is on the left, and the finished object is on the right. Use the attached STL file to print the holder. It printed easily on a Makerbot Replicator 2X. I printed it using the fine resolution, 0.10 mm layers.