Many people have talked about activities in the ports, so here's my plan for Barcelona to start that discussion:
Arrive BCN a.m. 17 Sep, taxi to U232 Hotel for check-in (or store bags if too early

).
Metro Blue Line to
Sagrada Familia (Gaudi architecture) for a look.
Metro Blue Line to
Le Pedrera (also Gaudi) for a look.
Metro Green Line to
Columbus Monument, followed by a stroll up
Las Ramblas stopping for lunch (tapas and sangria at La Zarzuela?), winding up at
Hard Rock Cafe for 1700 DIS meet

Metro Red Line to
Poble Espanyol de Montjuic (Spanish Village), then
Montjuic Fountain (Magic Fountain)

Finishing up with dinner at Filigrana then back to the hotel!
OCD?
This sound similar to my hoped for plans on 09/17.

I get to BCN at 7:55am, shuttle to hotel 10:30ish, store bags, hit the hop on hop off bus, HRC for afternoon drink meet, more sites, late dinner, sleep??? I had really wanted to do the segway tour on Saturday afternoon, but if
DCL isn't letting us off after we get on the ship, then that is out.
This is the hop on hop off I am looking at, it has three routes;
Discover Barcelona using three tour routes. Your ticket is valid on ALL routes.
Northern Route (Red Line):
Placa de Catalunya
Casa Batllo - Fundacio Antoni Tapies
Passeig de Gracia - La Pedrera
Sagrada Familia
Gracia
Parc Guell
Tramvia Blau - Tibidabo
Sarria
Monestir de Pedralbes - Col.leccio Thyssen
Palau Reial - Pavellons Guell
Barcelona Football Club
Francesc Macia - Diagonal
MACBA - CCCB
Southern Route (Blue Line):
Placa de Catalunya
Casa Batllo - Fundacio Antoni Tapies
Passeig de Gracia - La Pedrera
Francesc Macia - Diagonal
Estacio de Sants
Creu Coberta
Placa d'Espanya
Caixa Forum - Pavello Van Der Rohe
Poble Espanyol
MNAC
Anella Olimpica
Funicular de Montjuïc
Fundacio Joan Miro
Miramar - Jardins Costa i Llobera
World Trade Center
Colom - Museu Maritim
Port Vell
Museu d'Historia de Catalunya
Port Olimpic
Place de la Citadel - Zoo
Pla de Palau
Barri Gotic
Forum Route (Green Line):
Port Olimpic
Platja del Bogatell
Forum
Parc Diagonal Mar
Poblenou
Please note: the Green Line only operates between April 03 and September 27
Pj