• Place des Arts (Place des Arts metro station) and the Musée d'Art Contemporain there's a large terrace where you can listen to street musicians, catch some sun. It's also the site for some special events (Jazz Festival, Francopholies, etc);
• St-Denis' cafes (between St-Catherine and des Pins ave., the most recent and interesting restaurants and cafes are north of Sherbrooke);
• UQAM (Université du Québec à Montréal) central campus. The Judith-Jasmin pavillion is recycled from an old church (Berri-UQAM station);
• St-Louis square (north of Sherbrooke, west of St-Denis) and Prince-Arthur street, pedestrian street with cafes and restaurants just west of the St-Louis square, between Laval street and St-Laurent;
• St-Laurent blvd. north of Sherbrooke street, there's lots (and lots) of trendy restaurants (Buena Notte, le Globe, Luna, Insole, Cafeteria, etc) and bars;
• Laval street just west of St-Louis square and parallel to St-Denis, there's a lot of beautiful gray stone houses;
• Duluth street around St-Denis, the mecca for "bring your own wine" restaurants, although some restaurants charge you a $2.00 service fee to open and to serve the wine;
• the Foufounes Electriques, punk club almost as interesting from the outside than from the inside (St-Catherine just east of St-Laurent). It has changed names since (it's now called Fouf) and there's an Internet cafe on the ground floor.

Museums/Exhibitions :

• Cinémathèque québécoise and National Film Board on the corner of de Maisonneuve and St-Denis (if you like movies). The National Film Board has a ciné-robothèque: you sit in a big chair with headphones and you can select films (via a touch screen) and view them. There's a robot-arm that fetches the films (on laser disk) and puts them in a laser disk player for you. The Cinémathèque has a small movie museum (but it is currently being renovated).
• BibliothËque nationale (national library on St-Denis) between Ontario street and de Maisonneuve. There's no exhibitions usually, but it's great to walk around in it.
• Musée d'Art Contemporain (contemporary art museum), part of the permanent exhibition is outdoors in a sculpture garden. It's part of the Place-des-Arts (Place des Arts metro station).
• Place des Arts, concert halls and theaters. (Place des Arts metro station), there's an underground part to the Place that is accessible from Ste-Catherine or Complexe Desjardins (across the street from the Place). There are also two very nice gifts shop (near the entrance to the contemporary are museum).
• Just For Laugh (humor) museum, 2111 St-Laurent near Sherbrooke. They have various shows and exhibitions going on year 'round now.

Bars/Clubs :

• Shed Cafe (bar/cafe) trendy... 3515 St-Laurent.
• Fouf (aka Les Foufounes Electriques) (alternative/punk) on Ste-Catherine east.
• Metropolis (mega-dance-club) on Ste-Catherine near Laurent (and near the Foufounes), saturday night is Squeeze night, there are different places for different music in the club (rave, acid jazz, etc). It was closed for a while but I'm not sure if it has reopened.
• Angel's (dance-club) near the corner of St-Laurent and Prince-Arthur.
• Publix (resto-bar), near the corner of St-Laurent and Prince-Arthur.
• Le Swimming Pool club (2nd floor terrasse), on St-Laurent north of Prince-Arthur street.
• Café Campus on Prince-Arthur just east of St-Laurent, sometimes they have free shows on Wednesdays (look for the Polliwog).

P.S. Note that some prostitutes hang out at night around the corner of St-Laurent and St-Catherine or near the corner of St-Denis and René-Lévesque blvd. There's also some sex-shops and porno theaters around there. It's totally safe at any hour but i wouldn't walk around there with the kids, unless you want to be asked embarassing questions. That's in the south part of the quartier latin (between St-Laurent and St-Denis and between St-Catherine and René-Lévesque blvd.), the northern part is not "red-light district" like (north of Sherbrooke)...