CHANNEL SURFER: Fox Leaves ‘City’

Coming into the home stretch of the final week of the final sweeps period before summer, we’ve got tearful farewells, wacky guest stars, tantalizing cliffhangers and best of all … sexy stories about Florence Henderson!

ABC’s “Spin City” (9 p.m. EDT/PDT Wednesday) will be back next season with Charlie Sheen as its new star. But the bigger news is that Michael J. Fox will make his network TV farewell (hopefully only temporarily) in the series’ hourlong season finale. Fox will be taking a break from acting to use his considerable charm and energy to help the fight against Parkinson’s disease. Michael Gross, who played Fox’s TV dad in “Family Ties,” the series that made him a star so long ago, makes a guest appearance in this episode. Expect lots of hugs all around.

The season finale of “3rd Rock from the Sun” (8 p.m. EDT/PDT Tuesday, NBC) is a special one-hour episode featuring William Shatner and giant babe/WWF superstar Chyna in return guest appearances. Last year, the two were used in separate ratings stunts that were only moderately successful. Currently, Shatner’s hilariously self-deprecating series of ads for is causing a resurgence in the former Captain’s popularity. And Chyna, for whatever it’s worth, can kick your ass. Add in the shocking revelation that Dick (John Lithgow) is really the son of the Big Giant Head (Shatner), and this might be an interesting hour.

Also on Tuesday, Fox promises “the greatest find since King Tut,” as Hugh Downs hosts “Opening the Tombs of the Golden Mummies: Live!” (8 p.m. EDT/PDT). We don’t want to pick on the decision-makers at Fox, who are still trying to live down “Who Wants to Marry a Multi-Millionaire?” and perhaps don’t have the time to look more deeply into the genre of “opening things,” but shouldn’t Downs know better than this? After all, he used to work with Geraldo Rivera on “20/20” just before Geraldo decided it would be a good idea to open Al Capone’s “vault” on live TV.

Sunday night, meanwhile, (sort-of) brought us the goods on two famous couples: Greg and Marcia Brady, and Paul and Linda McCartney. So, just what really went on between Greg and Marcia? NBC’s “Growing Up Brady” dug up the dirt you wanted on the famed “Brady Bunch” duo. Barry Williams, who played Greg on the 1969-74 sitcom, executive-produced this TV movie (based on his autobiographical book of the same name) which promised “the affairs, the secrets and the scandals!” Cool! How does Florence Henderson fit into all of this? (Barely a peck.)

CBS, meanwhile, served up a much more sanitized brand of nostalgia in its biopic “The Linda McCartney Story,” about the 30-year romance between Paul McCartney (Gary Bakewell) (that rare, one-woman rock star) and photographer/activist Linda (Elizabeth Mitchell), who died in 1997 of cancer. If you are a fan of Paul, or the Beatles, this movie played sweet and sad, entertaining without offending. But it was also pretty bland.