There are two to choose from, both offering an action packed day out with a variety of features. We personally chose to go to the Aquaventure, located within The Atlantis Palm resort, as it was closer to our hotel and gave us the opportunity to see part of The Palm up close, as well at the renowned Atlantis Hotel. The other park is called Wild Wadi.
We booked our day out through our hotel's Tour Manager, for a slightly reduced rate of 260 Dirhams each, which included entry into the aquarium (inside the hotel) called 'The Lost Chambers'. I would advise pre-booking, as it really reduces your wait time when you arrive. *Note that transport is not included, but from JBR a taxi costs around 40 Dirhams, so is relatively inexpensive.