Ha ha

 I've already told you about the joke voted the funniest of all time (see post 17/10/09).  Here's the one which came second -

Sherlock Holmes and Dr Watson were going camping. They pitched their tent out in the open and went to sleep. Sometime in the middle of the night Holmes woke Watson up and said: “Watson, look up and tell me what you see.”
Watson replied: “I see millions and millions of stars.”
Holmes said: “and what do you deduce from that?”
Watson replied: “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.  Why, what do you deduce?”
And Holmes said: “Watson, you idiot, I deduce that somebody has stolen our tent.”