Now for a truly unique Facebook app
Introducing The Social Postal Service!
http://apps.facebook.com/socialpostal
The idea behind the Social Postal Service is simple - send free, physical cards to your friends for various holidays - starting with Valentines Day! Pick from 15 designs, type a message, an address, and you’re done. It’s that simple. Why poke friends on Facebook when you can ‘poke’ them in real-life with a real card? 
Each card costs ‘Card Points’, a unit of virtual currency that users earn by completing surveys from our advertisers. These surveys help to pay the bill, as it were, and makes it possible to send a physical product to our users.
The Social Postal Service also gives users the ability to send virtual ‘Conversation Hearts’ to your friends. These are those popular, colorful sugar hearts that always come out around Valentines Day with little sayings on them. You can send virtual versions of these hearts to your friends, customized with your own message.
Give the Social Postal Service a try and let me know what you think!