Eugene Volokh discusses mythical etymologies that get e-mailed around, despite being debunked by Snopes. These include:
Where did the word "picnic" comes from? It was typical to have a picnic on a Friday evening in Oklahoma. The word was short for "pick a nigger" to lynch.
...the claims that "nitty-gritty" originally referred to debris (including dead bodies) in the holds of slave ships, or that "handicapped" stems from handicapped people supposedly begging with their caps in their hands.
Eugene has some suggestions about such folk etymologies.
So do I. I suggest the more interesting word origin stories be called "entomologies" until they've been thoroughly debugged.