I agree with Dan about the Birthday Badge!! It is a really nice button...DS got one when we were at MK on his 4th birthday and every ride we went on, he got a sticker from a CM! They were great and most of them sang Happy Birthday to him!! LOL
When I turned 40 at WDW, I got a birthday card signed by Minnie and Mickey (still have it of course). I think someone at the front desk of the Coronado Springs clued them in (hint!!!)