Get Your Own Blanket
A man and a woman who have never met before find themselves in the same sleeping carriage of a train. After the initial embarrassment they both go to sleep, the woman on the top bunk, the man on the lower.
In the middle of the night the woman leans over, wakes the man and says, "I'm sorry to bother you, but I'm awfully cold and I was wondering if you could possibly get me another blanket."
The man leans out and, with a glint in his eye, says: "I've got a better idea. Just for tonight, let's pretend we're married."
The woman thinks for a moment. "Why not", she giggles.
"Great!", he replies, "Get your own blanket!"