I had never heard of thrumming, but when I saw Thrummed Mittens (here is the ravelry link), I HAD TO make plans to make them. This is what the pattern says about itself (which is WAY COOL!!!):
Unspun wool is secured to the stitches as they're worked, creating a fleecelike lining on the inside of the mitten and leaving a lovely pattern on the outside. As the mittens are worn, the wool felts, resulting in durable, extremely warm winter outerwear.Oh I can hardly WAIT to make these!!!
The great thing about Ravelry is you can see what others are doing and SAYING about the pattern! Here is a video that was linked to in the pattern on Ravelry: