The Vancouver Aquarium has a big marine mammal rescue and rehab program. We were able to see both a dolphin show and a whale show, both of which were a little unique since they featured harbor porpoises and Beluga whales.
No trip to Vancouver is complete without a visit to Granville Island (which is actually a peninsula). It has a long, rich history, starting out as just a sand bar and going though redevelopment a few times after becoming more of an industrial wasteland. It's accessible only by boat and the Granville Bridge, and is home to a wonderful public market and art community, with restaurants, galleries, shops, cafes and more. We even stumbled upon a quilt shop! If you're ever there, we had an amazing meal at the Sandbar restaurant and would highly recommend it to everyone!
We had a lovely ferry right back to downtown as the sun was setting, and the next morning we were back at Canada Place taking a sneak peek at what was on tap next.