A new sitcom with a veteran cast, “Crumbs” (9:30 p.m., ABC) is smart enough to challenge viewers with a mix of easy yucks, genuine pathos and some insight and character self-discovery. It also provides Jane Curtin with a venue for a standout performance, a tour de force balancing act of rage, self-pity and comic zaniness that is a sight to behold.

Fred Savage stars as Mitch Crumb, a Hollywood scriptwriter with a paralyzing case of writer’s block. He’s also gay, a fact he thinks he has kept from his family. While this could be the whole subject of a lesser comedy, Mitch’s life in the closet is but a minor theme in the “Crumbs” symphony of dysfunction and denial.

In the show’s well-crafted pilot, Mitch returns home to escort his mother, Suzanne (Curtin), home from the psychiatric facility where she was held after trying to run down her philandering husband, Billy (William Devane), and his new girlfriend. Eddie McClintock rounds out the cast as Jody, Mitch’s brother, who took over the family restaurant after Billy’s departure. Jody resents his father for deserting the family and the business, and he dismisses Mitch as a rich Hollywood jerk who turned their private tragedy – the drowning death of their brother – into a screenplay.

Unbeknownst to everybody, Mitch is broke and washed up. And his return to set things right with his family becomes a prolonged stay in which he tries to work out his own repressed emotions. This is all pretty heavy stuff for a sitcom, but “Crumbs” leavens the talk of medication, repression, hospitalization, grief and abandonment with standard sitcom one-liners. And that’s where “Crumbs” runs into trouble. The complex story and the characters’ emotional depth continually run into the limitation of the format.

But back to Curtin. She steals this show right from under her experienced co-stars. Hell, it is said, hath no fury like a woman scorned. And as the dumped Suzanne Crumb, Curtin gives one hell of a performance.

Tonight’s other highlights

¢ Tom Bergeron hosts “Dancing with the Stars” (7 p.m., ABC).

¢ Karen throws a party on an episode of “Will & Grace” (7:30 p.m., NBC), performed before a live audience.

¢ A casino owner’s mysterious demise on “CSI” (8 p.m., CBS).

¢ Marissa on their minds on “The O.C.” (8 p.m., Fox).

¢ An act of karmic penance demands that our hero work at a fast food joint on “My Name is Earl” (8 p.m., NBC).

¢ Accidents will happen on “The Office” (8:30 p.m., NBC)

¢ Rookie mistakes on “Without a Trace” (9 p.m., CBS).

¢ Scheduled on “Primetime” (9 p.m., ABC): a husband’s deadly secret; conformity and the herd mentality.