Here is my version:
When we moved into our house last year, there was a pile of extra floorboard, from when the previous owners had put down the hardwood floor in our downstairs. I used one of the longer boards (76cmm x 13cm) and painted it white with normal white emulsion paint. It required 2 coats.
The lettering was bought on ebay - this company do various different sizes and colours and you can choose your font- I went with pink and silver- size 75mm for my 'Fi's Birthdays' lettering and size 25mm for the month letters. The font for both is harrington. It was very reasonably priced and super easy to apply.
The circles are wooden and I bought them from WoodCraftShapes. Possibly not the cheapest, but they will drill the holes for free which seemed a good deal to me :-) I bought 3 packs of the 38mm x 38mm x 3mm size. I painted the circles using some little pots I had in my stash (not sure where they came from) and then used a black promarker to write the names and date on each circle. I have written the year of birth on the back too to keep me right with when big birthdays come up. They are then attached to the board with little hooks and 8mm silver jump rings from Beads Unlimited.
I've seen a few other examples of boards with hearts for anniversaries and my plan is to buy some of these to add in too, as well as some more Birthdays that I still need to attach.
Lastly I attached two small 'D ring' hooks to the back so that I can hang it up!