Television comedy takes an amusing step back in time with the new sitcom “Baby Bob” (7:30 p.m., CBS). “Bob” recalls such silly classics as “Mr. Ed,” “Bewitched,” “I Dream of Jeannie” and other shows based on an amazing, supernatural or even unnatural secret in the sitcom household.

“Bob” stars Adam Arkin and Joely Fisher as Walter and Lizzy Miller, ordinary parents of a 6-month-old boy who discovers that he can speak. And we’re not talking about “Ma-ma” and “Da-da.” Bob converses like a wise-cracking adult, or in Lizzy’s words, “like a Teamster from Chicago.” Ken Campbell provides the voice of Bob.

While it seems a bit creepy at first, Bob’s computer-generated baby banter is the only thing remotely funny about “Bob.” An early scene where Walter and Lizzy are host to their in-laws (Elliott Gould and Holland Taylor) for dinner features some of the blandest sitcom writing in recent memory. Gould even makes a Lewinsky-era joke about Bill Clinton, four years after the fact.

Still, a talking baby can be a powerful engine for laughs, and “Bob” doesn’t miss too many opportunities. Once Walter and Lizzy reconcile themselves to their gifted child, they resolve to keep his talent a secret so he won’t be exploited as a freak. Lizzy’s attempts to keep Bob quiet during a trip to the supermarket are genuinely funny, as is Bob’s reaction to a nontalking baby. The makers of “Bob” know they are treading on classic sitcom territory. The Millers live in a Santa Monica house clearly inspired by the old “Brady Bunch” domicile, complete with that hideous central staircase.

Some will find a talking baby hard to resist. The gimmick has worked well in commercials and in those “Look Who’s Talking” comedies. But it remains to be seen if viewers will return week after week for a show that relies on one joke, and so far, one star. The dialogue written for the grown-ups is just too weak to sustain “Baby Bob.”

 In contrast, good writing and ensemble acting highlight a standout episode of “Everybody Loves Raymond” (8 p.m., CBS). Chastised by Debra for being too immature around the children, Ray decides to have a serious talk with Ally (Madylin Sweeten) about the birds and the bees.

Only Ally isn’t as concerned about how babies are born as she is about why we are born in the first place. Her question “why did God make us?” throws Ray and the rest of the Barones for an existential loop. Robert is particularly hilarious while describing his late-night musings about God, eternity and the meaning of life.

Tonight’s other highlights

 Joe Rogan is host to a 90-minute “Fear Factor” (7 p.m., NBC).

 Live comedy on “The Colin Quinn Show” (8:30 p.m., NBC).

 A mother asks Lynn to stop her daughter’s participation in a religious cult’s mass wedding ceremony on “Family Law” (9 p.m., CBS).

 The death of an AWOL soldier on “Crossing Jordan” (9 p.m., NBC).

 Sam’s son’s behavior complicates his feelings for Judy on “Once and Again” (9 p.m., ABC)

 Scheduled on “Real Sports with Bryant Gumbel” (9:05 p.m., HBO): Curt Schilling; young skaters; Ted Nolan.