Lot's of places to eat, drink with an outdoor seating. Also here you can find a night club, which for Aveiro is a rare thing. In the mornings there is a fish market, where you can find fresh seafood.
It's the night life center of the city. I recommend: Adamastor for seafood and fish, Alicarius for a beer and a "francesinha", Morgan & Jacob's Guesthouse for a talk and a drink, Clandestino... etc...