Never tried one. It's a kind of American biscuit from what I gather, similar to Digestives. However, I've now found another source claiming the graham cracker was invented by Rev Sylvester Graham in the 1830s. Haven't found another inventor for the Allen key yet though (except one tongue in cheek site which claimed it was developed by Ikea!)
Quite right, Kit! A graham cracker is a slightly sweet biscuit made of whole wheat flour. They're very popular with young children (graham crackers & milk). Mothers prefer them to cookies because they're a healthier snack.
Try them sometime...they're DELICIOUS!
My understanding was that a Mr Allen had a company manufacturing these in the 30' 40's since gone out of business. The proper engineering term for them is a 'hexagonal socket wrench' although generation after generation still uses the old term.