For those amongst you who don't know it. The concept is: the system gives you an adress of a random postcrossing member and a unique code! Then, you send that person a postcard with the unique code! When this postcard arrives at its destination, the receiver puts the unique code into the postcrossing sytem and it registers that this postcard has reached its destination. Drom the moment one of your cards is registered, your address goes to someone else who has to send you a postcard... The more postcards you send, the more postcards you receive! Its an amazing way to get to know the world and a good activity to do with your children!
This is the website: http://www.postcrossing.com/
Today I've sent 4 cards to these countries: Russia, Belarus, Germany and Holland.