Here's my personal favorite JW urban myth:
A brother worked as a janitor at a college. He was also a genius.
One day, a supposedly unsolvable math problem was written on the markerboard in a classroom that he cleaned. (You can see where this is going.) Day after day the problem remained unsolved on the board until one day, the brother decided he would take a stab at it. He picked up a marker and went to work.
When the professor arrived the next day and found the problem solved, he demanded to know who solved it. No one came forward. Hearing of this later, the brother decides to come forward and claim his work. Somehow he was able to prove that he alone had cracked the code.
The university staff decided that a brilliant man like him needed to be rewarded, so he was given a full ride scholarship that wouldn't interfere his pioneering, (as well as some cash).
The person who related this to me was giggling the whole time, he said he didn't have the heart to tell the old sister telling the tale that it was the plot of Good Will Hunting.