If not for knitting, cavemen wouldn't have been able to keep warm throughout the winter or regularly re-gift Cosby sweaters. Weave your way to higher fashion with today's Groupon: for $15, you get $30 worth of yarn at Looped Yarn Works.

Colorful twists of yarn line the walls of Looped Yarn Works, supplying knitters with the strings needed to craft sweaters, socks, and caps. The shop's savvy knitting staff assist novices in navigating the extensive inventory of yarn, which includes everything from basic Cascade 220 wool ($6.60) to sturdy strands of Samson's hair. Madelinetosh DK ($21.60) glazes its 100% super-washed merino wool into a variety of solid-colored noodles, and the Classic Elite Ariosa's cashmere and merino fibers ($11.50) can form scarves that won't pill or accidentally become self-aware. Merino wool, alpaca, and viscose converge in the Rowan Felted Tweed DK ($19.95), and the Frog Tree Meriboo hosts an eco-conscious meeting of soft merino and bamboo ($7).