Picture: littlebrownpen on Etsy
The urbnCal from Stockholm has been featured on many Swedish blogs lately. This is a bigger Parisian version. It's held together by clips and you can rearrange the numbers using it for as long as you want (watch the video). Available from here. Would be fun to make something like this yourself. A friend of mine did an advent calender taking pictures of herself with different numbers around the city. Then she sent the pictures by mail to her friends. It took a few days to figure out what it was but it became a very popular project and she had to do it all again the next year.