If you a ready for nice silent walk, it is recommended to walk along the seaside of Barcelona at late evening time ;) Let say, it is possible to start at Olympic Village and end near Rambla street ;) On the way you will see Barceloneta quarter, as well as Port Vell.
If you decide to walk further to Rambla street, it becomes loud and touristy, but, anyway, it is nice opportunity to see how lively is the capital of Catalonia.
Like Elliot Smith brilliantly put it, Barcelona is a "beautiful place to get lost". Get lost in the small and dark streets of Raval and Barrio Gotico. Walk into the most dodgy-looking bar you can find, and you will have the time of your life. Seriously. Forget Puerto Olimpico and people-watching on the Ramblas. That's for tourists who don't have anything better to do. Feel the real Barcelona, talk to random strangers and walk into random places. And Barcelona is probably one of the best cities in Europe to do so!
Dress Code: Who cares?
No need to go too far! just outside Arts Hotel you have the trendiest area for dancing and having a drink, "Port Olimpic".Lots of bars,pubs and terraces, facing the port.Really nice place.
Dress Code: Jeans and trainers! dressing up! any...you are in Barcelona
If you're lucky, you can find one of those events where the designers of the town are selling their stuff of the last season! Beautyfull clothes and articles...