Hi -
Just because we often vacation mid-to-late August and just because DD's birthday falls in there, she's had several birthdays at WDW.
Always the birthday button. I let them know on reservations and on check-in. At WL, DD and DS got chocolate WL totem pops, an autographed pic of their favorite characters, and a balloon. DD has gotten several pins from CM's, including a special light up one at Epcot, along with a certificate. She's been sung to at Chef Mickey's and applauded by the crowd at another small Epcot show.
There was a great birthday thread on here awhile ago - do a search and I'm sure you'll come up with many other things.
Happy Birthday!!
melomouse