This is why I love the Wikipedia: It has not only an article on things like Allen keys, but a whole series (along with the enclosed diagram) of various kinds of screwdrivers.
Not what you would find in a regular encyclopedia, is it?
Applied Abstractions
Espen Andersen's take on technology, strategy, and many other things
Applied Abstractions 
It’s scary how many of these I have the correct tool for; and how many things like a chain saw require really odd ones.