Back in elementary school there was a girl in my class who thought a stapler would only work on paper. To demonstrate this she tried to staple her tongue, thinking that it just wouldn't work. Well, it did.
I Used to Believe (http://www.iusedtobelieve.com) is a website dedicated to the fanciful mis-beliefs of youth. Anyone can go there and post an anecdote about something they thought was true when they were younger.
Often times these revolve around unintentional puns and homonyms, or mishearing a common word, with concepts such as "gorilla cheese sandwiches", "pushy cats", and the "cross-eyed bear Gladly" led to some funny misunderstandings. Other times, euphemisms were taken literally, with one girl becoming a neat freak after learning an uncle had died by "biting the dust"!
I thought, in kindergarden, in order to read a book you had to read the page then turn it around and wave it back and forth. Little did I know the teacher was just showing us the pictures and it was not required if you were reading to your self.
The site has a number of different topics to browse and add to, from "religion" ("I though Jerusalem was a suburb of heaven") to "food" ("Chocolate cake was made of chocolate. Carrot cake was made of carrots. And my mom wondered why I never ate her sponge cake ...") to the perennial kid classic, "bodily functions" ("When I was little I used to think that white people had pink poop (I am brown so my poop is brown.)"). Every category is a smorgasbord of misinformation and possible fodder for future parents to lead their kids astray.
Recently, the site produced a book, Butter comes from Butterflies, filled with the beliefs found on the website. It can be purchased through the site.
When I was about 6 years old I went to church for the first time and someone there told me that God was everything. I then pictured God to be a giant pile of household appliances and furniture, mostly consisting of washing machines and couches.