by emmett, published
This bracelet has no clasp; instead you can stretch it over your hand and onto your wrist. It was inspired partially by the Springamathing: http://www.thingiverse.com/thing:12053. The design on the outside was inspired by MakeALot's link bracelet: http://www.thingiverse.com/thing:7354.
UPDATE: At the request of nycdesigner, a couple of alternate designs are now also available.
This bracelet is meant to print as a single layer thick. Stretchlet.stl has a thickness of 0.4mm, so it skeins up fine on my TOM. Then I remembered joris' trick with http://www.thingiverse.com/thing:8488, so Stretchlet1.stl creates the same shape, as long as you use zero infill, zero extra shells, and zero solid layers. It is also a smaller file and renders faster in OpenSCAD.
These STLs have an inside diameter of 55mm, so scale as necessary. You can also adjust the parameters in the OpenSCAD file, and it will print out the resulting diameter. The springiness works great with ABS, and apparently PLA works as well.