Which actors have Twitters?

Besides Charlie Sheen.. I already know he has one. But most of the Twitter people are musicans. Is there any actors that do have Twitters? Or are they too busy to have one? Like Aston Kutcher, Demi Moore, Natalie Portman, Sandra Bullock. Seems like none of them have Twitters. I'm just curious though I'm not a creep! If you were thinking that!!!