Claire Townsend of http://SmallStars.etsy.com had a very bad day at the laundromat a while back. Despite being a costume designer and handling fabric for a living, shes not always careful with her own stuff. Some of her vintage sweaters from the 1950s and 60s accidentally made their way into a dryer full of jeans. They came out much smaller and very felted.
http://blog.etsy.com/article/8010/ (see the full blog post for more information)