A man walks into a bar, sits down and drinks a beer.  Then he
drinks another beer, and another and...soon he needs to take a leak.
He's standing at the urinal in the men's room, when he looks over and
notices three black men standing at the other urinals.  He notices
that the one in the middle has a white cock.
   He zips up and, still a bit confused, goes back to the bar.  He
orders another brewsky and mentions to the bartender, "I was in the
men's room and noticed three black men in there.  I swear the one in
the middle had a white cock!  The bartender says, pointing, "You mean
those three guys at that table over there?"  "Yes", the man says,
"They're the ones."  "Well," replies the bartender, "those guys aren't
black.  They're coalminers.  The one in the middle must have gone home
for lunch."