Quoted:
A lot to see depending what you're into:
Old Montreal section of the city is really chock full of stuff: http://www.vieux.montreal.qc.ca/eng/accueila.htm
Notre-Dame Basilica: http://www.basiliquenotredame.ca/en/
Museum of Fine Arts: https://www.mbam.qc.ca/en/
Museum of Modern Art: http://www.macm.org/en/
Museum of History and archeology: http://www.pacmusee.qc.ca/en/home
Biodome (indoor zoo if it rains) http://espacepourlavie.ca/en/biodome
Botanical Garden: http://espacepourlavie.ca/en/botanical-garden
Restaurants:
You have to either go to http://www.lestersdeli.com/ http://reubensdeli.com/ http://www.schwartzsdeli.com/ and get a smoked meat sandwich
also:
http://www.joebeef.ca/
http://aupieddecochon.ca/ (you need reservations for this one)
BTW, the subway is safe here and much cheaper than parking in old montreal, it's also electric so you won't choke to death on fumes.
If you're driving: no turning right on a red in the city, the busses will blink to merge and they give 0 fucks so if you're not the 1st or 2nd car let them go
If you want to go to a titty bar you can touch (I heard this was not allowed in some states lol) but be warned that "Chez Mado" is a transvestite bar