Heidi from The Kundin Family made these crayon holders out of empty metal fruit cups:
They are even secured to a long white board so that they can sit at the back of a desk or the middle of the table without wandering off or tipping over.
I am so in love with this idea. The only problem is that I would want it on my desk and not in the girls room. Someone in our house is going to be getting something like this, but I am just not sure who yet.