Sherlock Holmes and Dr Watson go on a camping trip. They pitch their tent under the stars and go to sleep.
Sometime in the middle of the night, Holmes wakes Watson up and says: "Watson, look up, and tell me what you see."
"I see millions and millions of stars."
"And what do you deduce from that?"
"Well, if there are millions of stars, and if even a few of those have planets, it’s quite likely there are some planets like Earth out there. And if there are a few planets like Earth out there, there might also be life."
"Watson, you idiot, it means that somebody stole our tent!"
That joke won second place in the World's funniest joke contest. First place went to one of Spike Miligan's, which the person submitting did not attribute!