Misa De Gallo

      Misa del Gallo or Missa do Galo (literally rooster's mass) are the names given in Spanish and Portuguese, respectively, to the mass celebrated at midnight (or a bit before) on Christmas Eve. It is also known as "Misa de los Pastores" (Shepherd's Mass in Spanish).
Pope Sixtus III (5th century AD), introduced the custom of celebrating Christmas in a night vigil to Rome. At midnight "just after the cockcrow", ad praesepium (before the crib), in a small oratory located behind the high altar of the Basilica of Santa Maria Maggiore. The discrepancy with today's time for the cockcrow is due to the fact that ancient Romans set the cockcrow at the start of the day, i.e. midnight.
Some television channels broadcast the Pope conducting the midnight mass in Rome. In Spanish-speaking countries the custom is still upheld, specially in Latin America. In Venezuela it is also known as "Misa de Aguinaldo", referring to the traditional Christmas music known by that name. Other regions, such as the Philippines, the prayer is done early in the morning on Christmas Eve, and it is the last day of a nine-day ritual known as Simbang Gabi. Completing the nine days culminating with the Misa de Gallo is said to make a wish come true, and many Filipinos believe this centuries-old promise to this day. One of the customs related to the Philippine Misa de Gallo is the selling of traditional Philippine food, such as puto bumbong (a purple colored rice pastry, seasoned with grated--coconut and brown sugar), tsokolate (a hot chocolate drink), bibingka (flour and egg cakes cooked on top and under), and salabat, or ginger tea, which are sold by vendors to the faithful outside churches.

http://en.wikipedia.org/wiki/Misa_de_Gallo