oh...I LOVE Montreal, haven't been in 5 or 6 years though.
Walk up Mont Royal and take in the view.
The old cathedral is breathtakingly beautiful...Notre Dame I think?
Shopping or window shopping - Ste Catherine's Street.
There's a huge Casino just outside town if you like gambling...I've heard that the buffet dinner there is worth the trip in and of itself.
For a really nice dinner there is a place called Gibby's in an old stone building in the "old city"...best baked stuffed shrimp I ever had in my entire life. mmmmmmmmmm
have fun!!