Can Monkeys Really Imitate Other People?

Humans are so imitative it's absolutely crazy, you know. We're always looking round at each other, seeing what we're up to. And as soon as we see someone who's up to something, then we do the same thing. It's characteristic of all human beings and many, many animals. So where does that come from, and is it aveloped form of knowledge? What are child doing when they're playing? What are people doing when they're dreaming? And a what's the significance of the fact that you can imitate other people? Now i'll start with the last one briefly.