Clutter, junk, "stuff"- it happens. It accumulates almost on its own and takes over a closet or bookshelf as quickly as ants swarm upon a dropped piece of candy. Usually, you realize you're running out of space when you go searching for someplace to put more clutter. What to do? You can always toss it. Or donate it. Or you can find a way to reuse it. Here, I list some uncommon ways to deal with clutter:

Clothing-
Old "reuse" Donate or consign.
New "reuse" Cut up into cleaning rags. Sure, if you don't hem them, then those rags are going to fall apart very quickly, but that's why they're called "rags" in the first place. And there's nothing more convenient to have some lying around in the garage while changing the motor oil, or to have in the playroom when kids are painting.

Paper-
Old "reuse" Write/scribble on the backs.
New "reuse" Fold your own envelopes. Even better, learn origami or the art of paper folding. Amaze kids (the ones I babysit for are endlessly amused by me making paper boxes) and family, and maybe even make some pretty, original art pieces to display proudly in your house. No one has to know it was made from an ad you got in the mail.

Pens-
Old "reuse" Stick them anywhere you can think of- in the car, in your purse, in the office- for those unexpected "let me jot that down" moments.
New "reuse" Not for the faint of heart (and not exactly for everyday usage) but you could learn how to perform a tracheotomy.

For the rest of us, ladies, you can use a pen as hair accessory: Gather hair into a low ponytail. Hold a pen at the part where the elastic would go and begin twisting hair around the pen, like you're starting a bun. Make the bun tighter by turning the pen clockwise/counterclockwise (hair gets automatically twisted in the process). Weave the pen in and out of the forming bun to set it.

You can also learn how to spin a pen around your fingers. Just don't do it during meetings because your clients will pay more attention to the circus act rather than your contract negotiations.

Books-
Old "reuse" Ahh, books. You've already donated boxloads to the library, attempted to resell them at garage sales for 25 cents a pop, or traded them with friends like Pokeman cards.
New "reuse" There are lots of book-trading websites to be found, including bookcrossing where you "release" a book into the wild, leave a message of where you left it, and wait for someone to go pick it up. There's even a neat hunting/tracking feature so you can see oh where oh where has your little book been.
Paperbackswap is another book exchange site. For just the price of mailing, you can swap books; mailing books earns you good karma, or points, which allows you to request books from other members. From my experience, this site works quite well for best-sellers and what I would call "beach reads," or the popular books that you read when you (or your mind) are on vacation.

Happy decluttering!