The underwater viewing area for the whales, next to shamu stadium. Easy to miss but well worth it, very clear view and excellent photo ops.
Free beer in the hospitality house, 2 per adult.
If you're not traveling with little ones I would suggest the brewmasters beer making course, interesting for adults and free I believe.
The indoor show, don't remember the name of it, located in the back between the sharks and the horses. Good show, similar to Cirque du soleil but shorter and free.
Be sure to do Wild Arctic, its a simulator ride or a walk through, but it's the only way to get to the "Arctic" in which you can see the polar bears and other whales.
If you do have children the Animal Actors show is fun
And the dolphin show is all around great, much more than dolphins but I won't ruin it