By nature, when we find a deal, we spread the joy to others. Hence the popularity of group-based savings like Groupon.
Groupon is a coupon site that negotiates daily deals with retailers, which are unlocked after a certain number of people buy in. From there, the item or service remains on sale for 3 days, unless it runs out sooner. One of the best Groupon offers I've seen (and the first I've purchased) is today's Daily Deal. Buy a $50 coupon for Nordstrom Rack for only $25, usable through December 31, 2010. The coupon has been active since 12:05am on November 19, and almost 10,000 have been sold already, making sellout likely. Although the offer is available through San Francisco Groupon, it can be used at any Nordstrom Rack location.
If you're a frequent traveler of the Rack, there's no excuse not to buy it. But if you don't trust yourself to make it by the end of the year… Don't. Do. It.