I made this for my mom :)
To make it:
1. I attached 12 eye screws to the bottom of the board
2. Then I used a large circle punch (scrap booking section of Michaels) to punch an unnecessary amount of circles from paint samples
3. I used a teeny-tiny hole punch (also from the scrapping section) to punch holes at the top & bottom of each circle
4. I used jump rings (jewelry section) to attach the circles to the eye screws, as well as to each other
5. Add birthdays & decorate :)
I know this idea is floating all over pinterest, and there are 35785477 variations, so I'm not going to link it, since I have no idea who had the idea first, and I didn't follow any one example.