I used to live in the same apartment building that Mr. Rogers used to live in. When I was there, they re-did the elevator cabs to have plastic laminated panels on the walls with a little reveal between them. I would play with my keys on the elevator ride, and one day I put a key into this reveal and was inspired to design this little piece of modern furniture. Most key ring holders have little pegs on them that invite people to break them with much heavier things like purses and bookbags. This piece looks much cleaner, a bit more unique, and would be much simpler to make to boot.

Or, if you wanted to add a bit of functionality, you could add a lip to the top:

Or, if you wanted to still more functionality, you could cut some slots into the bottom as well, and then put some water jet cut steel hooks in:

I imagine there are a ton of ways to build around this horizontal slot idea, or incorporate it into other designs.

Models by MusicResponder, Roger Leighton, Luke, LukeyBoy, and marijke were used (from the Trimble 3D Warehouse)