It's Someone's Special Day is a song that figures out whose special day it was. The song was heard in the episode "Boots' Special Day".
Dora: It's someone's special day!
Boots: It's someone's special day!
Dora: Who's the special one whose day will be lots of fun!
Boots: On a special day, you get to play!
Dora: Go anywhere, here or there!
Both: Who's it gonna be?
Fiesta Trio: Who's it gonna be? Who's it gonna be?