INTERNATIONAL CELEBRATION - To American children, Christmas is portrayed as a time for sleigh rides in the snow and stockings hung by the chimney with care. But youths in other nations have their traditions, and that was the purpose of an International Week at Angell Elementary School last week. The object of the festivities was to acquaint the youngsters with customs of other nations, including the Mexican pinata illustrated here. Above, Angell teacher Jan Werner ties a blindfold on a youth who will try to find the hanging pinata and break it open to scatter the goodies inside. At right [this photo], Spence Bay, 6, rears back to smash the pinata, and free the candy for his friends. Other festivities included classroom visits by "international" parents, preparation of native dishes and costumes, and dance presentations.