TV highlights for Dec. 23: Title night on 'The Sing-Off'

FINALE WATCH: A winner is crowned after a double elimination on the Season 4 finale of "The Sing-Off" (NBC at 8 p.m.). Items found in unlikely places prove profitable on this week's "Antiques Roadshow" (PBS at 8). Items include a formerly buried Weller Coppertone vase and a collection of Cole Porter and Monty Woolley letters that were found in a dumpster.