Thrift stores seem to have more oddly-patterned ties than anything else. They're usually very inexpensive, completely outdated, and fairly unwearable. That doesn't mean they're unusable! I really like the idea of repurposing a men's tie into a wristlet.
If you're interested in making one like this, a tutorial is available here at The Reuser's Guide to Green Living (Update: Many readers have informed me that this tutorial is no longer available).
If you don't want to make your own, Tearful Touch sells these similar wristlets on Etsy:
Have you made one? Leave a link in the comments; I'd love to see!