[IROC]

Our daughter did this when she was about 3 years old. It went on for about 2 or 3 nights and I couldn't take it any more.

Here's what we did: Locked her in her room. It sounds cruel, but it's not. We explained to her (when it was bed time) that there was nothing wrong and that she needed to stay in her bed. We told her very calmly that if she gets out of her bed and leaves her room, we were going to lock her door (they make little plastic doorknob thingies just for this).

Anyway, the first night we went through this little ritual and she got up and walked out of her room. We put her back in there and locked the door and she screamed bloody murder for probably 30 minutes (seemed like hours) before she finally climbed in bed and went to sleep. The next night the same ritual - we calmly explained that if she left her room we were going to lock her door (and now she knew we meant it). She left her room and we locked the door and she screamed for about 10 minutes and then went to sleep.

The next night she was fine.

You gotta nip this stuff in the bud. IMHO you - as a parent - have to be fair, calm, but in control.