It’s pièce jaune time! You can pick up this nice foldable box (pictured) at the post office, fill it with all your pièces jaunes or yellow coins–the small change in the Euro Zone is yellowish or copper. Then bring it back in to the post office before February 15th and voilà, you have helped children in the hospital.
I never normally look at the coins much, but each coin is different on the back in each EU country. Some people were specially collecting Greek ones in the days when it looked as if Greece might leave the Euro Zone. In the photo below, for example, the harp denotes an Irish coin, and you can also see coins from Greece, Spain and the Netherlands. They are all valid anywhere in the Euro Zone, which is handy when you travel.