You can bring a wakeskate/rope/vest/etc & rent a waverunner on the local beaches or take a 30 minute ride into Cancun & ride in the lagoon behind a boat/tower.
My Friend wakeboarded in Cancun in that Lagoon and was shocked she was wakeboarding with Aligators. The instructors or Cabanna boys told her she is save as long as the boat is running. Aligators hate the nosie.
waterskicancun, Aaron posted the link above. Scott Smith's Supra Launch survived the hurricane. The lagoon offers some of the best butter in the world. The Alligators don't bite either, they are different from Crodociles.