A cutie mark appears on a pony's flank when he or she finds that certain something that makes them different from every other pony. - Miss Cheerilee

While there may be some fillies out there crusading for cutie marks on what seems to be a daily basis, several of their classmates have already had theirs appear. Haven't you always wanted to find out how it happened? Of course you have.

(The colt characters don't really interest me; sorry, colt fans.)