If you write about television long enough, you get jaded about sweeps stunts and the special gimmicks producers concoct to get our attention during this ratings-sensitive period.

Or perhaps you just ignore them. Does anybody remember the 3-D episode of “Medium”?

I rest my case.

With that in mind, tonight’s sweeps-tacular includes a “Scratch-n-Sniff” version of “My Name is Earl” (7 p.m., NBC). NBC has distributed stench-laden, number-coded cards in national magazines that will allow viewers to sniff along with tonight’s episode.

Given the squalid state of Earl and Randy’s motel room, the beer-soaked atmosphere of the Crab Shack and the unwashed condition of Earl’s El Camino, viewers should be in store for quite a snoot-full.

This comedy notion is a tip of the hat to “Odorama,” the olfactory gimmick devised by director John Waters for his 1981 comedy “Polyester.” Waters recently guest starred on “My Name is Earl” as a local mortician who ran a theme funeral home. He can also be seen as the host and “groom reaper” on the Court TV series “‘Til Death Due Us Part.” When I interviewed Waters for his part on “Death,” he expressed fondness for the NBC sitcom, saying that “Earl” reminded him of people in his home city of Baltimore.

Waters’ original Odorama device was a knowing nod to the 1950s Hollywood ballyhoo of B-movie producer William Castle. He enticed filmgoers to attend films like “The Tingler” by rigging theater seats with buzzers and by offering “insurance” to audience members just in case they “died of fright.”

Castle’s tricks were brilliant and memorable, but they reflected a film industry nervous about losing its audience to television. Now television appears to be repeating history, desperately trying to keep and attract viewers distracted by new media.

¢ The heyday of movie gimmicks like 3-D glasses and Cinerama arrived a few years after the era of film noir, those cheap black-and-white dramas with complicated characters, femme fatales and doom-laden plots. Isn’t it interesting that tonight’s episode of “Smallville” (7 p.m., CW) is presented in film noir style? The cinematic gimmick dovetails with a plot about Jimmy investigating life in the small town during the 1940s.

¢ When you’re on top of the ratings heap, you don’t really need a gimmick. As if to prove that more is more, “Grey’s Anatomy” (8 p.m., ABC) will simply air a two-hour episode about Addison’s departure for Los Angeles.

Tonight’s other highlights

¢ Commandos try to avoid getting crushed when they share a desert island with giant lizards and snakes in the 2005 shocker “Komodo vs. Cobra” (6 p.m., Sci Fi).

¢ Betty goes medieval on the concept of Secretary’s Day on “Ugly Betty” (7 p.m., ABC).

¢ Phyllis feels violated on “The Office” (7:36 p.m., NBC)

¢ The blackjack-dealing wife of a UFO enthusiast draws her final card on “CSI” (8 p.m., CBS)

¢ After a serial killer strikes again, Shark swings into action on “Shark” (9 p.m., CBS).

¢ A departmental dinner holds a romantic surprise on “ER” (9 p.m., NBC).