I'm not usually a fan of markets, but the Granville Island market (and the island itself) was a lot of fun.
First, there is the food. The market had fresh vegetables, fruit, meat, fish, flowers, bakery items, and lots of other food stuff from local farms and companies. I was like a kid in a candy store . . . or an adult in a candy store. We were looking for picnic items for a cruise on the water (see my boat rental entry). I expected to grab a couple things and be done in about 15 minutes. An hour later, we were still picking things out. By the time we had finished, I had eaten an ice cream cone, a bratwurst, fruit, and rice pudding. Plus, we had enough food for a crew of five. There were so many things that I wanted and the atmosphere was really fun. The market closed around 6pm on the Saturday we visited.
Second, there are the outdoor cafes. We had a couple of drinks outside at Bridges. You can watch the boats go by, people watch and just hang out. The weather was perfect, so it was an ideal day.
Third, there are usually live performers of some sort. We watched and listened to some musicians for about 20 minutes (this was during my ice cream phase of the eating).
Four, there are some fantastic art studios and artisans throughout Granville Island. Go from the market to the studios and you will find every kind of artist you can imagine (i.e. painting, sculpture, silk, baskets, metals, pottery, etc.). The artists are organized into a variety of collectives and you can actually see them working. This makes it much better than going to a fancy studio.
Finally, there a some other fun things to see and do near the markets. You can rent a boat, visit a museum (i.e. the model ship and train museum), go in the children's toy market, buy fish straight off a boat, or just roller blade around.