I would suggest any of the Royal Caribbean ships. They have an excellent, comprehensive children's program. In addition to the daytime program for Aquanauts (ages 3-5) they also provide well supervised group babysitting for $5 an hour from 10 pm - 1am. As you are obviously aware from your post, the only requirements are that children must be at least 3 yrs. old, potty trained, and pull-up diaper free.