As so eloquently stated in the 90s comedy Wayne's World: "It's party time! Excellent." (Now that Mike Myers has cemented his Canadian celebrity status by making it onto a stamp, a quote by him is reputable.) If you want to watch the dark night become darker and "just one drink" turn into "too many drinks" we have your party-central destinations in Toronto. Being the Canadian city with the largest population, Toronto's only problem when it comes to nightlife is too much choice.
You can certainly go the comedy route with a visit to Chicago's sister location of Second City, where Mike Myers perfected his comedy chops. Toronto also has the spots to entertain you musically, with live acts at places like The Garrison. You can also go to The Bovine Sex Club for rock and roll and not for what you were thinking. (Get your mind out of the gutter.)
There are other nights to sleep, although we don't know when, because like a fine wine, Toronto gets better with age. The city is waiting for you to get out and stay out.