* The Office (9/8c NBC)
It's delivery time for an eagerly awaited episode. Baby makes three, and Jim and Pam open a new chapter in their lives, in an expanded hourlong outing. Pam's contractions begin, spurring her and Jim to scramble to the hospital. As for their peers at Dunder Mifflin-turned-Sabre, the staffers try to comfort Pam with food and entertainment, and Michael nervously anticipates the birth. There are goings-on back at the office, too: Andy swells with jealousy when Erin has lunch with Kevin. Linda Purl reprises her role as Helene, Pam's mother and Michael's former flame.
* The Marriage Ref (10/9c NBC)
Jerry Seinfeld's latest project makes its official debut in its regular time slot. In this comedy series, for which Seinfeld serves as executive producer, married couples air their grievances before a rotating panel of celebrities. After the couples have presented their cases and the celebs have offered their input, host and Marriage Ref Tom Papa makes a call on who's right and who's wrong. Tonight's panel includes Seinfeld, Tina Fey and Eva Longoria Parker.
* Grey's Anatomy (9/8c ABC)
Following last week's repeat and the flashback episode two weeks ago, it's time to get back to what's happening now, and you can look for newcomers Teddy and Sloan to be front and center tonight. It has been tough for them lately, and Callie and Arizona will try to help. Meanwhile, the Richard-Derek tension didn't go away during the hiatus, and it flares up again when a famous surgeon (Chelcie Ross) arrives as a patient. His name: Harper Avery. Isn't that new doc Jackson's last name, too?
Michael really has himself in a pickle this time. Last week's episode ended with the big reveal that Gilroy was just a pawn for an even bigger, bolder baddie: the mysterious Simon. Now Michael has to maneuver his way through Simon's plans, which include potentially detonating a bomb in Miami while also dodging the prying eyes of the FBI. And since this episode is the season finale, viewers can be sure they'll get plenty of intrigue, action and surprises.
The drama mamas of Orange County close their fifth season with past and present housewives convening for a summer's-end party. But Tamra's marriage seems to be hitting a crucial crossroads, putting her in no party mood. Conversely, Vicki's relationship seems to be cementing, plus Gretchen and boyfriend Slade Smiley are such an item that they wear coordinating white outfits at the bash. Although this is the finale, leading ladies Vicki, Tamra, Gretchen, Lynne and Alexis return next week in a two-part reunion episode. And the franchise marches on with the Season 3 opener of Real Housewives of New York City, which airs tonight at 11 pm/ET.