* The Biggest Loser: Couples (8 pm/ET NBC)
Season 7 comes to a close in tonight's three-hour live finale. Last week, Tara and Helen secured their spots as finalists, while Mike and Ron's fate in the competition fell into the hands of viewers voting at home. All is revealed tonight as the third contestant is announced, the at-home players return for one last weigh-in and, of course, the Biggest Loser is named. Also, a new element is added to the finale as two potential contestants for next season are presented for viewer voting.
* Dancing with the Stars (9 pm/ET ABC)
Shawn Johnson, Gilles Marini, Ty Murray and Melissa Rycroft have now completed the semifinal round, which is quite an accomplishment. But there's still one more leg to go in this race. Is Gilles truly a lock to claim a spot in the finals? Can Ty's fan base help him escape elimination again? These questions will be answered tonight, when we find out which three are moving on to the finals. Also, Raphael Saadiq performs "100 Yard Dash," and the winning elements in the Design-a-Dance contest are revealed.
* Fringe (9:04 pm/ET Fox)
So the Observer has come for Walter, right after he discovered the original ZFT manuscript, including the missing chapter on ethics. And Nina Sharp has been shot, and presumably abducted, by hooded thugs. Is Olivia next? One thing we know about tonight's first-season finale is the appearance of Leonard Nimoy as Massive Dynamics honcho William Bell, who (we hope) will tie up some loose ends for this impressive freshman outing. Moreover, a second season has been ordered, so it's likely not the last we'll see of Bell.
* Frontline (9 pm/ET PBS)
How did financier Bernard Madoff pull off his massive Ponzi scheme, which bilked investors of an estimated $65 billion? Martin Smith delves into the long-running scheme, illuminating the swindle through interviews with Madoff associates, employees and investors, including Tremont hedge-fund founder Sandra Manzke, who placed some $3 billion of her clients' money into Madoff's hands over a 25-year period.
Now that The Real Housewives of New York City has closed its season, the sudsy franchise promptly crosses the Hudson River and lands in New Jersey to capture the real-world adventures of five indulged Garden State ladies. Tonight's premiere introduces these over-the-top Jersey girls -Teresa Giudice, Jacqueline Laurita, Caroline Manzo, Dina Manzo and Danielle Staub. It's all in the family this time around: For the first time in franchise history, the cast includes two sisters---and they're married to two brothers.