The revolving door separating cable and network series continues to spin. ABC now recycles episodes of “Kyle XY” (8 p.m., ABC) that originate on its cable cousin, the Family Channel. On tonight’s “Kyle,” a mysterious man burglarizes and bugs the Trager house.

Beginning Aug. 7, NBC will air repeat episodes of “Psych” (9 p.m., USA), originally created for USA, co-owned with NBC by Universal.

This follows a long trend of networks using their cable affiliates as a kind of minor-league training ground for upcoming shows, or programs that the networks were too timid to air in the first place.

¢ As we all know, the WB and UPN networks have expired and will join to become the CW network this September. Their canceled repeats continue to air, hovering like unhappy spirits caught between the world of the living and the twilight of syndication.

But shows like “CSI” teach us that we can learn much from the dead. And two WB repeats airing tonight offer a perfect opportunity for a sitcom autopsy that may show us why these shows, and their networks, succumbed at such a tender age.

They suffered from a malignancy known as Frequent Holiday Episode Syndrome. Few of us ever wanted to watch “Twins” (7:30 p.m., WB) in the first place.

But the notion of sitting through this crude comedy’s belabored Thanksgiving episode during a July heat wave is about as welcome as the prospect of eating a bucket of turkey and gravy on the beach. “Living with Fran” (8:30 p.m., WB) follows suit with a half hour of Halloween shenanigans.

I’m all for creative freedom, but I’d like to propose that TV writers take a solemn pledge to avoid the hallowed, hackneyed tradition of the perfunctory holiday episode. Let’s try it for a year. Without Halloween, Thanksgiving, Christmas and Valentine’s Day plot devices to lean on, they may just come up with something original. If this works, we may be able to stamp out TV’s biggest creativity killer: amnesia.

Tonight’s other highlights

¢ A mysterious powder puts the squad in quarantine on “NCIS” (7 p.m., CBS).

¢ The president learns not to mess with his first lady as another day’s work concludes for Jack Bauer on “24” (8 p.m., Fox).

¢ A seminar in torture techniques on “The Unit” (8 p.m., CBS).

¢ Impaired vision on “Monk” (8 p.m., USA).

¢ After a school shooting, figures lead to a surprising suspect on “Numb3rs” (10 p.m., CBS).

¢ Scheduled on “20/20” (9 p.m., ABC): an interview with an American who passed himself off as an English Lord; a report on a woman kept by her husband as a virtual prisoner for 10 years.

¢ “Greatest Moments” (9 p.m., CMT) looks back at the country music of the 1990s and the TV showcases of that era, including “Crook & Chase” and “Nashville Now.”