I'll PM you.
Spooky Slumber Party Games: Bloody Mary, Light As a Feather, Ouija & Spoon Bending
A 15 year old girl should weigh under 150 lbs.
150 / 5 = 30lbs per person
She won't levitate, but it'll sure feel that way when you're lifting something that would otherwise be 150 lbs with just your finger.
Chanting "bloody mary" isn't supposed to 'make something spooky happen' it's specifically supposed to summon Bloody Mary through the mirror who will then proceed to dismember the summoner. . .
But of course in a dark room any little bump, weird blotch on the mirror or snickering noises from the girls waiting outside will be perceived to be the chant 'working'.
Ouija boards have actually been studied and explained to death over the past 120 years since they were first patented in America in the 1890s as a novelty toy. http://skepdic.com/ouija.html
What's really funny about ouija boards is that in most stories about them, it's not the actual words they spell out. . . but it's the random other stuff that happens hours or days later which everyone decides to attribute to the Ouija Board for some reason.
Feeling someone breathing on your face at night. Lets assume for the sake of argument that this REALLY WAS some ghost breathing on your face at night. . . what does that have to do with the ouija board? Maybe your next-door neighbor summoned Bloody Mary or something.