The Oregon Zoo in Portland has a lights display every year in December. They have over 200 light displays throughout the zoo, many of them with moving parts. We decided to get together and take the kids this year when Mom was in town. It was very cold, but we had a good time and I know the kids really enjoyed looking at all the lights.
The kids always love to ride the train. During Zoo Lights, they have the trains all decorated and they had several running so you get to pass them every so often during your ride.