Doors and Cats

Have you ever heard the pawing of your cat, trying to get into the room you are occupying? Now here's another question. Have you ever had a cat who gets into the room, closes the door than can't get out? That is what we have here in Looney Land. Smoke, that crazy cat of ours does it on a semi-daily regular basis. We have had to put door stops in (loose weights, amp's and heavy stuff like that) in front of the doors so he won't lock himself in. And the worst of it, he always has accomplishes. Little Dottie and Meredith. His little harem. Besides the obvious of tossing him outdoors to fend for himself, what can a mother cat do?