Secrets of putting a two year old to bed?

I was just curious if anyone out there has a secret to getting a two year old to stay in their bed at bedtime?

It is a constant struggle to keep her from climbing out of bed and trying to play when she should be going to sleep. We have a set routine with her bath just before bedtime. Her twin sister doesn't have any problems going to bed. It's just the one.

It's driving my wife and I crazy. If anyone has any ideas. Please post them in the comments.