Pick up one of Mike's Pastry's famous canolli! They typically have huge crowds so go early and bring cash! (They don't accept credit cards.) If they are too busy, check out Modern Pastry across the street.
Top of the Hub has the best view of the city skyline, hands down. We recommend grabbing a drink at the bar and walking around to get a 360 of the city.
Check out the SoWa open market on Sunday for all kinds of local vendors - from food to clothing to art!