This will be a happy night of TV viewing at my house, because it's the finale of Gossip Girl (7 p.m., CW/Ch. 30).My daughters and I have watched all 120 episodes to date. Because we got hooked at the start and when it ran off the rails - about 19 episodes in, when Blair started dating a prince - we stuck with it, hoping that it would get better.It never really did. And it doesn't say much for us that we held out hope for 100 episodes.Actually, not quite that many. But at some point, we figured we had to see how all this ends. And when the good news arrived that the sixth and final season would be just 10 episodes, it seemed silly to stop watching.So we stuck with it. And mocked how terrible every episode was.Tonight, we get an hour of highlights and fond memories, followed by the hourlong final episode. We're supposed to find out the identity of Gossip Girl. Which hasn't kept me awake at night wondering, to be honest.And then it will be over. Hallelujah!Also tonight, NBC previews 1600 Penn (8:30 p.m., NBC/Ch. 5), the new sitcom about a wacky First Family which makes its regular debut on Jan. 10.The good news is that it will probably get a big audience after "The Voice." The bad news is that it's not a very good episode, which probably won't help "1600 Penn."I've seen two more episodes, and the show is growing on me. But I really didn't like this half hour at all.Elsewhere on TV ...NFL (6:30 p.m., ESPN): New York Jets at Tennessee TitansHow I Met Your Mother (7 and 7:30 p.m., CBS/Ch. 2): Barney plans to propose to Patrice, prompting Robin to take action.Extreme Makeover: Home Edition (7 and 8 p.m., ABC/Ch. 4): The team builds a home for a family who adopted five siblings.The Voice (7 p.m., NBC/Ch. 5): The final two vocalists perform. A winner will be announced on Tuesday.The Layover with Anthony Bourdain (7 and 10 p.m., Travel): Tony travels to Toronto.2 Broke Girls (8 p.m., CBS/Ch. 2): Caroline and Max are having trouble making their rent.Mike & Molly (8:30 p.m., CBS/Ch. 2): Molly goes on a holiday spendings spree.Hawaii Five-0 (9 p.m, CBS/Ch. 2): A young boy's father may be in grave danger.Take It All (9 p.m., NBC/Ch. 5): The finale of this game show.