"Grace is Easier than Brute Force"
to get the puck past your opponent:

If you're not familiar with underwater hockey, you might have a few questions. Like, do the players wear pads? And if so, where? The answers are swimming around this weekend at the University of Minnesota Aquatic Center, where 20 club teams from around the country are taking part in the national underwater hockey tournament. This is not the usual way the State of Hockey plays its game.
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Unless a lot of glass swimming pools are specially built, underwater hockey might not have much of a future as a spectator sport -- most of the action occurs on the bottom.

But clearer views are available. Ben Erickson, organizer of the local Minnesota Loons club and the tournament's director, pointed out the three underwater cameras and the digital video recording area under the empty grandstand. Feed from the cameras was also being shown on a large full-color screen.

The game itself is low-tech: Six players from each team scramble for the puck and try to slide it into goals placed on the pool's bottom. Referees wearing orange vests float above the play and signal to a land-based ref if something egregious happens, such as aiming the puck at someone or, Erickson jokes, the placing of a finger in a snorkel.