What was that CLANG I just heard?

A young man was planning to get married and asked his doctor how he could tell if his bride is a virgin.
The doctor said, "Well, you need three things. A can of red paint, a can of blue paint and a shovel."
'The man was astonished and asked, "So what do I do with these?"
The doc replied, "Before the wedding night, you paint your one ball red and the other ball blue. If she says, 'That's the strangest pair of balls I ever saw' you hit her head with the shovel."

- http://tofts-andy.blogspot.com