Cats are naturally nocturnal (they're awake at night, and sleep during the day). Cats who live with humans, and are kept indoors, usually adopt the sleeping habits of their humans. My cats, for example, are awake during the day, and go to bed when I do.

They roll around like that, sometimes to scratch an itch. Other times to show submission, playfulness, or affection. Try petting him next time he does it.

As they get older, they mellow out. My 7 year old cat is more lazy than my 9 month old cat. But she has her moments!

Some cats like string, lasers, toy mice, balls... Or anything at all. They have different taste just like people.