The Paper Clip
Book mark: No more dirty looks from the librarian when you return dog-eared books
Scotch-tape end holder: You could buy those trade-marked plastic gadgets to keep the end of the tape from adhering to the roll. Or just slap on a paper clip and wrap the end around it.
Pirate earring: Arrrrrrgh, this'll keep 'em out of yer jewelry box!
Ornament hanger: Who remembers to stock up on those little metal hooks for the Christmas tree? Just unbend a paper clip into an S shape.
Sunglass repair: When that tiny screw pops out, separating the arm of your glasses from the frame, just slide a paper clip through the hinge. If you really want to seal your reputation for frugality, leave it that way.
Chocolate-candy hanger: Friends and family won't object to chocolate candy hung from the tree with care. How to do it? Bisect a paper clip into two U-shaped pieces (use a pair of heavy-duty kitchen scissors). Push the two-pronged end into the top of a chocolate candy, leaving a U-shaped loop sticking up, and then slide the end loop onto a branch.