A kit project I've been working on needs a six-foot clamp and either two- or four-foot clamp (depending on the kit) for assembly. I don't feel that I can tell the purchasers to go buy the necessary clamps for just this one project; so I tackled the job of trying to design a clamp that'd be so inexpensive that it could just be discarded once the kit had been assembled.
The stock is either 1"x6" or 2"x6" (again depending on the particular kit) being glued to make a box. My design supports the full 5½" on one side and applies pressure to the exact center on the other side - regardless of the thickness of the stock (within a ±½" range).
It was an interesting trig/geometry problem; and I'll post photos on ABPW of the surprisingly simple solution - perhaps the idea will come in handy to someone else one day.