Cathy,
There's also a theme park near Montreal, you could take the Metro to get to it called . One of my favorite and unique venue is the . I've loved it and so have my younger cousins who we have taken there as well. It's on the Montreal '76 Olympics Village site so you'd see the Olympic Stadium and everything. They also have package tickets so you could visit the Biodome and take a ride up to the to of the Olympic Tower, depending on the time you have.
Downtown Montreal is great with shopping and all that,
Old Montreal is popular with the tourists as well as the Old Port, you could stop buy an pick up a
'Beaver Tail' which is a Pastry, not an actual tail.
Finally, you're in the city at the same time as
The Montreal Internation Fireworks Competition, this is the only festival I can think of at this time of year. It's fantastic if you can catch any of the performances. A particularly good spot is the close the Jacques Cartier Bridge, a huge bridge linking the Island of Montreal to the South Shore, you can walk up the bridge and (safely!) watch the fireworks being set off, many of them going off almost at eye level as you're up so high. Don't worry the bridge is safe with 3meter fences on either side.
If your tour is taking you anywhere around the outskirts of Montreal
One note,
Canada Day is July 1st and you could catch the festivities wherever you are as theres free events and concerts in all major cities.
As you can probably tell I'm a Montrealer, but will tell you, if you're going to Kingston and your tour doesn't include the
Thousand Islands, be sure to get yourself on a boat tour of the Waterway, on a nice day you'll be thrilled with the scenery and you can keep yourself busy counting the Islands!
Let me know if you need any more information or you are thinking about going somewhere and want some advice!