Scoot with a GPS
Barcelona proudly claims to have more scooters per capita than any city in Europe— the great weather, the ease of parking, and the low cost make them an ideal for getting around. Vesping rents classic orange Vespas, and also offers a six hour guided tour of the city, or programmed tours: of the 1992 Olympic sites and improvements, a beach tour, a tour of Gaudí's architecture, or whatever you want. Or you can just zoom off on your own with a GPS.
Rental includes a Vespa S 50cc, two helmets, a full tank, GPS, lock and insurance; and they'll deliver them to the hotel.