Sharx was always a must-see for my friends when they visited me in Montreal, and now it's on my list for the times when I myself come back. And it's not just because of the cute waitresses in little black skirts, or the 2 for 1 happy hour. Though those help.
Sharx is primarily a pool hall, with at least fifty tables and plenty of room to spread out, though they also have a lounge and game area, and even bowling. It's essentially a huge, dark, concrete basement, but with a cool club vibe that keeps it from feeling dingy.
The food isn't half bad, either. I was there bowling on a Friday afternoon at the same time as somebody's office party, and they shared all the finger food with us--one time there was such a thing as a free lunch.