Fridays and Saturdays are dominated by a cosmopolitan mix of tourists, and stag & hen parties. Sunday nights are busy with locals as many shops and restaurants are closed on Mondays. Most of the action is centred around La Rambla, the wide boulevard stretching from Placa de Catalunya to the Port Vell. There are usually street entertainers wowing the crowds - mime artists, clowns, acrobats, flamenco dancers etc. Wandering the streets adjacent to La Rambla - the Gothic district (Barrí Gotic), Raval and Born will reveal many fun bars, often aimed at students and budget travelers. However you need to be aware that La Rambla can be dangerous in the late evening.  Port Vell itself has a modern complex of 5 clubs and bars at the top - they start to fill at 1AM and continue until about 5AM. Port Olympic has the Casino and many little bars and clubs around the Marina - most relatively downmarket and cheesy, but good fun. If you walk along Barceloneta beach from the Casino there are 3 very lovely restaurants that turn into modern classy lounge bars/ clubs at 1AM.  There is also BaJa Beach Club infamous for its scantily clad dancers (both female and male) and a magnet for the hen/ stag do crowd.  

Razzmatazz is a very large and popular nightclub with lots of events  - Missy Elliott played recently - and is widely acclaimed to be great fun with a choice of 5 different music types. City Hall Night Club off Placa Catalunya has 2 different music areas and a large outside area - perfect for late night chatting. International Night on Mondays is good fun with a variety of nationalities wearing their country sticker with pride!

For people in their 30ies (or who think that way!) top bar recommendations are: Shoko (on the beach near the Port Olympic Casino - particularly good to lounge on the day beds on a Sunday or to go to the club after 1AM), Bar Lobo (behind Hotel 1898 at 109 La Rambla, with good cocktails - try the mojito); avoid eating here though - there are better places, Patagonia (great ice-cream, below and 1st floor bar is a fantastic place to sit and watch the world go by on La Rambla), Bar 111 (just opened on the corner of Le Meridien 5* hotel La Rambla) , Sinatras (off Placa Reial/ off La Rambla - a modern Irish bar with great service and excellent fusion restaurant above) & Hotel 1898 Bar at 109 La Rambla (good for sitting in the bar from midnight until 2am or so and chat with people).

Bar Marsalla, located on the Carrer Sant Pau, opened in 1820 and looks like it hasn't been changed much since then. The place is usually crowded as people pack themselves in to enjoy the bohemian ambiance. The bar is known as a place to drink some absinthe, a powerful drink popular when the bar first opened its doors. A slotted spoon, a sugar cube and small bottle of water are served with your order of absinthe to facilitate the ritual of drinking the liquor. This involves placing the sugar cube on the spoon, dipping it into the absinthe, lighting it on fire and then extinguishing it with the bottle of water so that the sugar drips down into the drink. 

There are a great number of live music jam sessions, jazz music, blues, rock and flamenco acts. Many people see in the latter a great number of business opportunities, hence they charge ridiculous amounts of money for a flamenco session - and usually it's not even good! Instead, look around for local flamenco bars and sessions - they're just waiting to be found.

If you are into more "alternative" bars and events, and want to steer away from the tourist crowds around Port Olympic and Las Ramblas, this student guide has weekly info, news and listings on what is happening in the "real" Barcelona.