Woven Art carries a smaller, but carefully chosen selection of yarns. The focus seems to be on natural fibers (including more exotic ones such as bamboo!). About half of the stock is hand-dyed by the shop owner, and she's willing to dye yarns to suit your preferences - but her tastes are very nice and all the yarn is lovely.
The shop also offers roving and spinning supplies. Classes are offered in spinning (including the carding process), weaving, crochet, knitting, and dyeing. The classes are very reasonably priced - roughly ten dollars per two hour session. The shop is cozy, with several nice chairs to sit in, and the staff is friendly and helpful. The shop participates in local events like "Be a Tourist Day" and is often open late (with food or goodies for those who stop by!) during special events in downtown East Lansing. My only regret is that I can't come by more often!