The food building alone makes a trip to the CNE worth the ticket price. There are other things going on there, like carnival rides and games, but we spend most of our time there eating, like people who make awesome life choices.
I recommend the following: deep fried cookie dough, deep fried mars bar, Chocolate Supreme chimney cone from Chimney Stax, and Fran's blueberry pie milkshake. Also, a trip to the CNE isn't complete without Tiny Tom's tiny donuts.
They also have Pokemon, both digital and stuffed. I didn't win any of the latter, but I sure had fun trying.