What sources are there to the rural legend that if somebody slaps you in the back of your head while you cross your eyes, they’ll stick that way?
Peace,
mangeorge
I considered just posting a reply saying that I don’t know, but that would probably have made only me laugh, and only when I’m as tired as I am now. But for what it’s worth, Snopes aside, I remember reading in a kids’ Interesting Facts book that if you shut your eyes and look up while they’re shut, you won’t be able to open them again until you look straight forward again. Now that’s just patently untrue. Go on, try it… oh, you already did. see? And this was written as pure fact! Also Barbara Woodhouse once wrote that a dog physically cannot bark while it is lying down. Once again, WRONGO.
Don’t know what you’re going to do with the above non-information, but you knw it now. I hope you find out about the cross-eyed myth soon.
I couldn’t find the source of any of those on Snopes, or anywhere else for that matter.
A couple more I can’t find the source of are;
Drinking pickle juice will make your hair fall out.
Eating burnt toast can make your hair curly.
Father Maloney had a curly fringe around his bald pate.
Don’t know much about his diet, tho.
Anyboby?
Peace,
mangeorge
The problem is that there probably isn’t going to be a documented source for any of these. They are perpetuated by word of mouth, and usually started by normal people trying to make sense of a confusing world. You might find some of them as far back as Roman writings, or even earlier documents, but there will still be a question as to whether the writer came up with the superstition or is just passing it on. And new ones are being thought up every day - as a programmer, I have run accross a lot of people who think you have to do A & B to get a program to run, even when I know that is completely unnecessary.
It’s been a long time since I’ve read about superstition and magic(I read a lot about them when I was a child) but I think sources can be grouped into these basic types: primitive observation (Red sky at morning…) ; Sympathetic magic (easter eggs and bunny, both symbols of fertility); wishful thinking( wish upon a star); appeasing or confusing good or bad spirits(crossing your fingers, throwing salt over your shoulder).
I’m sure there’s some other causes - check out a book on superstitions, it really is fascinating reading.
However, I have a WAG on some of yours - I suspect some of them were made up by moms tired of their kids annoying behavior. 
And you forgot about the activity which makes you go blind and grow hair on your palms. 