MAC Musée d'art contemporain de Montréal
In the heart of summer festival headquarters (JazzFest, Francofolies, Nuits d'Afrique, Just for Laughs)
I don't usually like museums but this one is so modern and has really thought-provoking art. I've always had fun there for the few times I went.
Contemporary Museum - check out their website to see what exhibit is up.