Sónar
A annual three-day music festival held in Barcelona, Spain. It is described officially as a festival of Advanced Music and Multimedia Art. Music is by far the main aspect of the festival. The festival runs for three days and nights, usually starting on a Thursday in the third week of June.
Festes de la Mercè
Barcelona's main annual festival around the 24th of September, encompassing many events such as which group of 'castellers' can form the highest human tower, live music events, firework displays and processions involving wooden giants. All of this is accompanied by a heavy consumption of Cava, the national drink of Catalonia.
Festes de Gràcia
The Festes de Gracia is a Catalonian celebration, held around the 15th of August each year to commemorate the Assumption. During the week of festivities that mark one of Barcelona's most important fiestas, the city of Gracia explodes with fun, excitement, colour and fireworks. Many streets are decorated by the neighbours, live music, food in the street, and the parties continue all night.
Festes de Sants
Similar to Gracia's event, but smaller and later on in August. If you can't go to the Gracia's, try go to this festival instead.
Sant Jordi
23rd of April. Considered to be like Valentines Day. People give roses and books around the streets. Traditionally men give women roses and women give men books. It is one of the most popular and interesting celebrations in Catalonia.
Corpus -Late in May (Corpus Christi day)
An egg is put over the fountains (most of them in the churches, and decorated with flowers), and "magically dances" over the water. Most of the churches are in the city center: Cathedral's cloister, Santa Anna, Casa de l'Ardiaca, Museu Frederic Marés, and over 10 more fountains there are over 15b people live here.
Fira de Santa Llúcia
From December 2nd/3rd to December 23rd, to commemorate Sta Llúcia (December 13th). In front of the Cathedral, is where the Christmas objects are sold. Some places sell Christmas trees, but most of them sell elements for making the pessebres, the representations of the birth of Jesus that people uses to put at home. These include small sculptures, wooden pieces and moss used to simulate grass.
December 13th is the feast day of Santa Llucia, patron saint of fashion designers and blind people, who gather at the Santa Llucia chapel in the cathedral to pay their respects.
Revetlla de Sant Joan
This is the midsummer solstice celebration. It is celebrated on 23rd June every year and is signified by the fireworks that are permanently on display during this time.
Fira de Barcelona
All year you have events and fair services in Barcelona. The Feria Internacional de Barcelona organisation was not officially constituted until 1932. The International Exposition was held in 1929.
La Mercé (few day before Sept 24)
Another day that is famous, but not that important. It is holiday and the city offers a lot of activities to have fun. Enjoy fountains and fireworks show at the base of the Montjuic hill.