The Plainville Historic Center, 29 Pierce St., is scheduled to participate in the holiday tree lighting and downtown festivities on Thursday, Dec. 6, 4 to 8 p.m. All museum rooms will be decorated and open for visitors as will the museum store. The store is offering the book “Connecticut 169” by Marty Podskoch. A raffle is also planned. People of all ages are welcome to stop by for hot chocolate and cookies with "Auntie Claus" (Santa's sister). Children also may decorate cookie.