It's becoming a new tradition at our house for the Birthday child to have a birthday shirt. It's fun to wear something made just for you on your birthday and it makes it easy to tell what year that birthday photo is from :)
I did Jay's birthday shirt with a simple number cut from a scrap of fabric and ironed on using double sided steam-a-seam. You could also just embroider it on.
Then I cut things from fabric that he has really loved this past year to make it "his" shirt. He loves all things that fly.
Kay's birthday shirt got us going on this tradition. She's had a love-of-all-things-piggy-year.
Some other birthday traditions for us are to measure up on the Growing Walls that I did made for each of the kids (and take a picture there).
And we also like to make a hand print of the birthday child with ink for the family scrapbook. It's fun to compare how hands and height have changed over the years.
I would love to hear your ideas on fun traditions too!