I have been planning this project since we moved over a year ago and just got it finished a few weeks ago. A friend reminded me that I had forgotten to take pictures since I hung it up, so here you go!
I brought the door jamb from our old house laundry room with us when we moved. It had all the kids' heights marked from when they were old enough to stand still and measure until about 2 months before we moved and I started readying the house to sell. I transferred all of those heights and then measured our current ones. There is a gap of about 15 months between when we took off the door jamb and when I hung the new ruler. They grew SO much in that time! I was shocked!
Anyway, I'm thrilled with how this came out and love having it on my wall!
Oh, and as far as method, I consulted several pinterest links, used a fence board that I found in the shed, a sharpie marker and a couple of coats of poly. The only thing I'd do differently next time is spend the money on a board that isn't warped. This one bows out from the wall a little and annoys me. I'd prefer it to lay FLAT. Oh, well. Still thrilled!