There's a bookstore in Portland, Oregon that will take your Kindle as a trade in for store credit. Microcosm Publishing are running this offer to the end of the month, and it's only good at their store (mail-in not accepted). So someone has to be there in person (which they would anyway, in order to haul away the loot).
The offer is for either $139 or $189 in store credit (not cash), and it's only good for the Kindle.
I don't know if they really thought this through. I checked, and I was told that the offer was good for any Kindle, and they didn't specify that it had to work. I have a dead original Kindle (and a friend in the area). I'm tempted to send it to my friend as a belated birthday gift.
Check before you go. I'm not sure they'll accept old or dead Kindles.