Thats a given. One of the main reasons we are going up is to visit family. I have an uncle who lives in St Catherines and we are spending three days there with him and Niagra Falls is definitely one the list of things to do. The wife wants to go watch the locks too.
Two days with family in Guelph as well before we make the trek towards Toronto for Canada's Wonderland on a day and then to downtown for the Jays game.