Here's a portion of the Gamedaily review of Endless Ocean, thankfully free of silliness:
Nintendo provides you with lots to do. As you run across different forms of aquatic life, you can log them in a personal encyclopedia. It works in the same fashion as a Pokedex would with Pokemon creatures. In addition, you can also train a dolphin to do tricks, and it will swim alongside you as you explore.
Furthermore, the game lets you work with others, such as taking pictures or leading fellow divers on tours. You won't encounter any missions involving agun or dangerous pirates, but an experience like this doesn't require them.
Seriously, this game looks interesting! As interesting as No More Heroes? I dunno, but it is $20 cheaper.
One more thought:
At the Guildhall we've been talking about what constitutes a "game." Obviously in many ways Endless Ocean doesn't really qualify- but what it does qualify for is that it provides "play," that is, a wide open arena to relax in.