What To Do When In Barcelona, Spain

Stroll along the following famous streets:
Las Ramblas, a tile-covered tree-lined pedestrian walkway, the busiest and most lively street of the city. This street has an excellent atmosphere and is full of local artists, street entertainers and pavement cafes. It is also a large tourist haunt; so expect to pay higher prices for food and drink. Head off into some of the side streets for a cheaper, more local, experience of Barcelona.
La Plaça Catalunya, emotional centre of Barcelona.
El Portal de l'Àngel, a commercial pedestrian road.
Cruise miles of beachfront boardwalk starting from Barceloneta or get a tan on the beach.
 
Platja de la Barceloneta Looking onto Port OlímpicWander the Barri Gotic, the largely intact medieval centre of the city.
Enjoy the nightlife in the city's 200 or so squats.
Walk in Born, a very popular area with great restaurants and places to have a few drinks.
Be on the beach every Sunday night throughout the summer for live music, drinks and swimming.
Check out Gràcia: a neighbourhood just off Park Guell, full of local culture, few tourists, tons of Places for relaxing and eating.
Visit flamenco show in a real tablao. Tablao de Carmen that is situated in Poble Espanyol offers a spectacular flamenco evening. The cheapest entrance fee (31 Euro) includes the 1.5-2 hour show, drink and free of charge entrance in Poble Espanyol
Ride cable way to get from the sea front to Montjuïc mountain. 7.5 Euro for one-way ticket. This is however currently not available, as it is undergoing renovation.
Check out Montjuïc and its green surroundings, where you can also admire the German minimalist Ludwig Mies van der Rohe 1929 Pavilion (link or the interesting Caixa Forum building (right in front of the Pavilion).
Sit for a while in Plaça dels Àngels, while admiring the whiteness of the MACBA and the best street skate tricks in town.
Catch a performance at the beautiful Teatre del Liceu and the Palau de la Musica Catalana.