Original Penguin takes 40% off full-price items, or an extra 50% off sale items, via coupon code "CYBER" as part of its Cyber Monday Sale. Plus, coupon code "OEXTRA20" stacks to take an extra 20% off, as does code "OEXTRA10" for an extra 10% off. (That's a total of 57% off full-price items, and an extra 64% off sale items.) Better yet, all orders bag free shipping. Combined, that's the best set of stacking coupons we've seen from Original Penguin. Deal ends December 2.