I was browsing through a book named 'Five Hundred and Seven Mechanical Movements' and stumbled across the following clever device:
It basically takes a worm gear, which normally looks something like this:
And remaps the worm (something cylinder-like) into a disk.
Using my mastery of Solidworks, I constructed a solid model of the worm disk concept and improved it somewhat by making multiple teeth engage instead of just one.
Note that the spur-like gear pictured mating with the worm gear would need to be angled in order to mesh properly, this just demonstrates the general concept.