If you like the water show at Las Vegas' Bellagio, this is created by the same folks. We parked in a free lot off of 6th St and Harbor Blvd, near the Maritime Museum, and took the Red Car Line to the Swinford St stop, which let us out right to the Fountain.
My young kids were captivated by the water show choreographed to music. When the music was not playing, it was fun to watch the fountain shoot up in different patterns. The infinity pool is pretty cool, too. There was a sign that said no swimming or entering the fountain waters, but that does not stop some of the visitors/locals from doing so! Just down the street on 2nd St is an interactive fountain where it is "okay" for people to get wet if they want.