This is probably the safest area of Mexico. It is one big tourist playground.
I recommend using TripAdvisor.com to evaluate recreational opportunities. Alot of people enjoy the eco-parks Xcaret and Xelha. We spent 7 nights at the JW Marriott with our 9 and 12 year olds. When the waves weren't too big we were able to boogie board and bodysurf right in front of the hotel. My daughter had her hair braided by a lady on the beach. There is a waterpark just down the road, but a bit pricey and we skipped it. Definitely worth doing a day trip to the ruins--either Tulum or Chichen Itza (we actually spent 2 nights at Chichen Itza in order not to be rushed). We don't like overscheduling our vactions, so we didn't do too much while there, but there are plenty of opportunities for snorkeling, parasailing, boat trips, scuba lessons, jetskiing, etc.