ABC launches another family sitcom tonight -- which isn't exactly news, except that this one is watchable.
* "The Adventures of Brisco County, Jr." (8-9 p.m., WBFF, Channel 45) -- To quote directly from one of the songs in "Hair": "Answer my weary query, Timothy Leary, dearie." What I want to know, Mr. Leary, is this: Were you eager to play Dr. Milo in this strange TV Western, or were you a little Leary? Fox.
* "Sister, Sister" (8:30-9 p.m., 9:30-10 p.m., WJZ, Channel 13) -- Yes, it's a dumb premise: Twin sisters, separated at birth, reunite, and the respective single parents who adopted them decide to live under one roof for the good of the girls. But was the "identical cousins" premise of "The Patty Duke Show" any better? With real twins (Tia and Tamera Mowry) instead of trick photography, and with Tim Reid and Jackee Harry as the parents, this is a smoothly running family show from start to finish. Better than any of ABC's "Full House"-"Family Matters"-"Step By Step"-style sitcoms, it's almost a lock to be just as popular. My 11-year-old daughter road-tested the first two preview tapes, and was charmed from the opening scene. Let's hope ABC doesn't lose track of the adults in this sitcom, because they're the main thing keeping me in the room. ABC.
* "The X-Files" (9-10 p.m., WBFF, Channel 45) -- In tonight's first-run episode, Scully (Gillian Anderson) and Mulder (David Duchovny) go on the trail of a man called Horse. No, wait. That's not quite right. One of the guest stars is a man called Horse -- Michael Horse, one of the supporting players on "Twin Peaks" -- who plays a sheriff. He teams up with Mulder and Scully to chase a mysterious animal, or spirit, Mulder suspects is a manitou. Whatever it is, it's a worthy opponent: At halftime during this particular episode of "The X-Files," the score is manitou, Mulder 1. Fox.
* "Picket Fences" (10-11 p.m., WBAL, Channel 11) -- Twelve angry men, and women, "Picket Fences" style: Guest star James Earl Jones is an attorney who brings an especially controversial case into the "neutral territory" of Rome, Wis., where Sheriff Brock (Tom Skerritt) is selected as jury foreman, putting him instantly at odds with guest star Richard Masur. CBS.
* "Late Night With Conan O'Brien" (12:35-1:35 a.m., WMAR, Channel 2) -- Little more than a month after he made a guest appearance on "Late Night," David Letterman is back -- or, at least, a repeat of that show is. NBC.