There was an episode of "House" about a cat who supposedly predicted death. House concluded that people had low grade infections which made their body warmer before they died.

Well, it's a well-known behavior, Cats love Warm places, ppl have a fever when caught a disease and barely move on the bed, these kinds of factors make their side a perfect place for cats!
the same reason explains why cats love laptops!

I have no idea if cats can really do this, but I would not doubt it. Cats have the ability to sense stress and pain in individuals. Every time my wife says she is in pain she is surrounded by four cats, always the same cats, who sleep near her but not touching her. Many times one tries to sleep on her head. He usually ends up on the pillow near Kate's head. Cats give her lost of interesting times as she finds them funny to watch. They know all about their surroundings. In case you cannot tell I like cats also. I get two to sleep by me if I am doing something special for them.