It was a holiday weekend in the East Village, starting with Santacon. O.K., enough about Santacon. The annual tree lighting ceremony took place on Sun., Dec. 10, in Tompkins Square Park, drawing about 200 neighborhood participants. The Mandel / Lydon Trio provided musical backup for the singers from the Theater for the New City and the crowd, who happily sang along to Christmas carols and one Hanukkah tune. Veselka owner Tom Birchard was on hand to provide free hot chocolate and a birthday cake for Crystal Field, the executive artistic director for TNC, who has organized and sung at the holiday event since she started the whole shebang 26 years ago.