You've probably seen instances of knolling without knowing there was a word for it. Knolling at the Apple Store:
Knolling the contents of your bag:
Knolling a recipe for a book:
Knolling the parts of a machine:
Knolling is the practice of organizing objects in parallel or at 90° angles. The term has been popularized by artist Tom Sachs; he picked it up from Andrew Kromelow when both were working at Frank Gehry's furniture fabrication shop. Gehry was designing chairs for furniture company Knoll, and Kromelow would arrange unused tools in a manner similar to Knoll furniture. Hence, knolling.
Update: Things Organized Neatly is really something. Lots of knolling.