The Grand Canal Shoppes at Venetian/Palazzo is quite pretty during the holidays when they put up festive decorations. Nice place to take pictures, it's a lovely stroll along the canal. But the restrooms are a little hard to find and not easily accessible if you're in a time crunch (dock a star).
Free attractions by St. Mark's Square
STREETMOSPHERE - noon-6pm on the hour, except 3pm, performed by singers, actors, and musicians
LIVING STATUE - on display 10am-6pm - performer poses as marble statues for guests to take pictures with (tips encouraged), amazing how long they stand their motionless for a long time
Gondola Ride: Reservation must be made in person, usually see a long line on weekends. Rates are $21 per person for shared gondola (seats 4) or $84 for private gondola (for 2).