MOO cards, an offer I got when I upgraded my account at Flickr. (By the way the cards rock, I plan to order a full set or two of 100. If you've been thinking about doing this go for it!)
In the package was a thank you note with coupon and it said that an additional coupon was inside. I didn't find it and was mumbling to myself when Lucas took the box from me and started ripping it open. Oops! We're in trouble now!