If you go, you can see dozens of beautiful balloons flying during the day. Some of the balloons have special shapes. You can see them for free from several parks in Saint Jean. If you want to go to Saint-Jean-sur-Richelieu, it is a 20 minute drive from Montreal. Look at the map here.
They also do balloon take-offs at night, but you have to buy a ticket to see them. You can also take a ride for $150-$190.