In my OAC year of highschool (i.e. Ontario grade 13) I had my uncle's batman costume. So a couple friends and I got the idea to tape a whack of physics equations on it and add "FizixMan" ontop of the bat symbol.
An extraordinarily long trip to the washroom stall later, first period rolls around and I run into my physics class as FizixMan! (Even wrote the test that day in the suit) What a load of fun that was; my two teachers (posed in the picture with me) couldn't get enough of it. A legend was born; they still tell the story aboot me to their students.
But I didn't tell them my secret identity… nobody knows… maybe nobody ever will… >.>
(oh and also… I'm KNEELING in that picture… you'd be surprised at how many people think I'm THAT short… 
)