Posadas are held in neighborhoods across Mexico and are also becoming popular in the United States. The celebration consists of a procession with candles, sometimes with individuals selected to play the parts of Mary and Joseph, or sometimes images are carried. The procession will make its way to a particular home (a different one each night), where a special song is sung. In this song those outside the house sing the part of Joseph asking for shelter and the family inside responds singing the part of the innkeeper saying that there is no room. The song switches back and forth a few times until finally the innkeeper decides to let them in. The door is opened and everyone goes inside. Read the lyrics and translation of the posada song.
Inside the house there is a celebration which can vary from a very big fancy party to a small get-together among friends. Often the festivities begin with a short Bible reading and prayer. Then the hosts give the guests food, usually tamales and a hot drink - like ponche or atole. Then there are piñatas and the children are given candy.
The nine nights of posadas leading up to Christmas are said to represent the nine months that Jesus spent in Mary's womb, or alternatively, to represent nine days journey to Bethlehem.