My oldest is almost three and she started with this behavior when she was about 19 months! It continued until just a few months ago, so hang in there, as they work through year 2 it does get much better. Like your daughter, my oldest is also very smart and has spoken clearly and lengthily since she was very young, in fact, I felt like I was reading about her when I read your decsription! Anyway, I found that it helped to put her to bed with a few little toys or animals and books. My daughter loves to read and even "reads" books to herself that we have read together. I'd let her pick two and she would calm down when we put her to bed. It still works to this day. We also use time out if she is rude and screaming out of control, or if she hits her little sister. We tell her to sit until we say get up, wait two minutes or so, and ask her if she's "ready" (she usually is), then make her apologize to the baby or us if we were the target, though unfortunately the baby usually is! Finally, I read the book 1-2-3 Magic and I use the counting to 3 ideas he outlines. It gives her a chance to correct the behavior before you hit 3, then if she doesn't, the consequence has been outlined and you MUST follow through. For example, if she refuses to go upstairs to get ready for bed by the time I hit 3, if she hasn't moved, I carry her up. I have to say - when I do that she ALWAYS cooperates. She knows I mean it! You might want to read that book, it's a quick read and it outlines strategies for different ages. Good luck and remember, it will pass!