Code CCK2248 will net you one free greeting card from Cardstore.com through Sunday, August 26, at 11:59pm EST. You get free shipping as well, so you shouldn't pay a dime for this. The deal is in celebration of Grandparents Day, which is September 9th.
I used to make fun of these card offers, but then I had a birthday, anniversary, and wedding all creep up on me and dang it if those earlier freebie cards didn't come in handy. Note that those were three separate events, not one giant bash. Although now I kind of wish I could attend at least one birthnniversadding in my life.