Reply #10: I agree with what everyone else said, and then add my own two cents.

[Interrobang]

You may have to (if he continues biting and clawing) grab his paws (put your thumb between his claws and his foot-pad) and force him to retract his claws. A few gentle taps on the nose might also help to get the point across if he's really slow. I had to do this with my cat when I first got him because he hadn't figured out that he was a BIG cat (about 15lbs) with huge oversized claws and teeth (his fangs hang down over his lower lip so he looks like Dracula!), because he was tearing my hands to ribbons. Now he understand that hands are not for playing with, but he's not the sharpest spoon in the drawer. (Really obedient, though, once he understands what you mean. How many cats do you know who lie down on command?)

If that doesn't work, and he still doesn't calm down, you may want to have him checked for Addison's Disease, which is a problem with epinephrine (adrenalin) uptake, where it doesn't break down in the body and causes almost perpetual overexcitement. Eventually, it leads to alimentary problems, arthritis, cysts, hair loss, and death, and overstimulation hastens the progress of the disease. If you should find out that he has it, you'll want to switch him immediately to a low-stress, no-play, no-excitement routine, and the most digestible food you can find.

Hope that helps.