Extreme Couponing is the act of buying a rediculous amount of products at a retail store (usually grocery) for next to nothing. For the most part, the items are purchased in rediculous quantities through the use of coupons. In some cases, the store may end up owing someone money. This "overage" may be creditied to other items (such as beer or meat products).
I was stuck in line at the store for half an hour because of some nut-job house wife, all thanks to extreme couponing.