The Cutie Mark Chronicles

Every pony with a cutie mark has a different story to tell about how he or she earned it. Taking a break from pursuing their hidden talents, the Cutie Mark Crusaders decide to ask Rainbow Dash and the others about their marks. They soon discover that one particular story has a surprising connection to the other five.
My Little Pony; Friendship is Magic - Season 1, Song #11: "So Many Wonders"