All of the above.
The Just for Laughs Festival is still on this weekend, so there should be plenty of street entertainment and festivities throughout the city. That alone should keep you busy between mouthfuls for smoked meat, poutine and mile-high strawberry cheesecake.
The Montreal Museum of Fine Arts is also excellent.
http://www.mbam.qc.ca/en.
And just to be clear, the "Canadian Ballet" and the Montreal Ballet are two wildly different animals.
