Every year around Christmas, the theatre group La Trapa stage the Pastorets (Shepherds) at the Agrupacio Congrés centre, in the Sant Andreu district. The version they perform, and have done since 1999, is Els pastorets i l'estrella de Nadal (The Shepherds and the Star of Christmas).

The Agrupació Congrés has three sections and theatre is the oldest one. It is divided into different groups, according to age. They put on two or three plays each season, but all the groups take part in the Pastorets. As well as La Trapa, there is a traditional dance section, the Esbart Joventut Nostra, and a table tennis section. The Agrupació Congrés was set up in 1956 as the Asociación de Familias San Pío X in the neighbourhood housing centre, which was new at the time and called Viviendas del Congreso. Initially the group's aim was to foster relations between the inhabitants of the new Congrès neighbourhood, as well as integrate them in the city.