- THE SMOTHERS BROTHERS have had it with CBS's "now you see them, now you don't" treatment since they started taping a series of variety specials for them last year. First it was going to be a one-shot 20th anniversary special. Then it was a limited mid-season series. Then it was a series for the fall. Then it wasn't. Then it was another mid-season special. Then a series of specials.

And now CBS wants to keep ordering additional specials. According to their manager, Ken Kragen, CBS has asked the brothers to tape four more specials in addition to the four already shot this season. But the brothers are finally saying "No.""It would mean having to cancel engagements at Harrahs and the Desert Inn and places like that," Kragen said. "We've already had to do that twice because of the variety show, and it's not smart. It could reach the point where the clubs figure they don't need the Smothers if they can't depend on them."

So the bad news is there will be no more Smothers Brothers variety segments. But the good news is the brothers continue to work on developing a sitcom for next fall. At least, I think that's good news.

0- SANDY HILL has been replaced on ABC's Home show by former "Incredible Sunday" co-host Christina Ferrare. Of course, if you watch "Home," you already knew that. But you may not have known why she left. According to ABC sources, Hill was not excited about the show's new hour-long format, particularly because it meant spending more time at ABC's "Home" and less time at her own. So the show's producers and the star reached an amicable agreement, and Hill was allowed to return home to her family.

And just in time, too. Have you been following the show's "Sex at Home" series this week? "Six Steps to Becoming an Orgasmic Woman." "Sex After Menopause." "How to Alleviate Male Impotence." You'd think Hill had been replaced by someone named Rivera.

- AND SPEAKING OF FERRARE, how is she able to cover both "Home" and "Incredible Sunday"? She doesn't have to. "Incredible Sunday" has been canceled (surprise, surprise), and will be replaced Feb. 26 with a new one-hour series called Great Circuses of the World. Mary Hart ("Entertainment Tonight") will host the new series, which will feature "circus acts indigenous to each nation, from Brazil to Poland to Mexico, Sweden, Japan and elsewhere."

The new show will also provide a heck of an opportunity to showcase Hart's heralded gams in lots of circus-y fishnet stockings.

- AND WHAT OF RIVERA, he of the broken nose and shattered journalistic reputation? Geraldo Rivera continues to claim that he is a victim of bad press, and that he is doing some of the most aggressive, responsible journalism on television today. And to prove it today he presented another one of his unique, hard-hitting reports on an issue of urgent importance: Nudism, direct from a foaming hot tub at a nudist resort in Palm Springs, Calif., with six nudists - and a bare-chested Rivera.

Up tomorrow: "Sex in Prison."

By the way, would it surprise anyone to learn that the February ratings sweeps started on Wednesday?