If you are a classification junkie, this will make you salivate: The Collier Classification Scheme for Very Small Objects, a project by Brian Collier.
An attractive, clean and intriguing website design, a very cool classification scheme for things that might have previously been considered "square pegs". An interesting choice of everyday English instead of Latin for the taxonomy. Don't miss the introduction, which I found fascinating.
Check out the database of collected and classified very small objects. Don't you want to collect, classify and contribute one of your own? I'm going to be looking in my library corners for something very small that just screams to be collected and classified.