On your birthday, if you talk to nurse Joy, I believe she will give you a birthday cake prop for the Pokemon musicals(not sure if this is true so if someone will test it they will know for sure and tell you). I also know that there is a place that is usually foggy, but on your birthday it isnt foggy. It is a reallly pretty place and i think it has a waterfall but i forgot the name. I read this in the Pokemon Black and White guide book. Im really sorry I don't know the place. but I hope this helped! ;)