Yep, sail away and tropical night. They last about an hour. Loads of fun. the one on tropical night is late, after you leave Cozumel (10:30), but worth keeping the kids up for. Like you could really get them to bed that early on the ship anyway......
My DS 8 missed it because he wouldn't come out of kids club and now has seen the pictures. He's not real happy to have missed it. He keeps giving me grief about it and I just tell him to have his dad re-book the cruise and he can see it!