My son had his birthday at WDW a couple of years ago. He got a cupcake at Chef Mickey's (for breakfast, none the less
), but that was it. Mickey Mouse did make a big deal out of his birthday, because it happens to be Mickey's birthday too
. Mickey was pointing to his birthday button, then pointing to DS button to show they shared their special day!
Otherwise, CM's stopped and said happy birthday all day. He also had a fair number of guests do the same thing, which is always a good way to share that Disney spirit!