We liked 70's night. We also really enjoy the family cabaret shows on the 7 day. They usually have the entertainers from the variety shows in and it's family friendly fun. They have a more adult cabaret show after 2nd dining, but we never made it to those. Probably try one or two on the Christmas cruise.
For a little more quiet time, there are always movies showing late in the evening, and they are usually geared toward the adults.
I've seen people playing ping pong on Deck 9 some nights. Relaxing with family/friends in the tropical breeze. Can't get better than that!