As if pro football doesn't already threaten the very fabric of the American family -- what with the forward pass, Monday Night Football, gambling and the Super Bowl -- our time away from the television is about to be reduced again by a newfangled viewing game of live football strategy.

It's called QB1.

By 1990, QB1 might lure a nation of armchair quarterbacks into a permanent state of immobility. Who's ever going to stand up again on Sunday afternoons? This game could replace the Hula-Hoop, the pet rock and Trivial Pursuit as the most enduring, most captivating, most fascinating, most entertaining and most fulfilling fad of the generation.

And it's all so simple, even lawyers and lobbyists could grasp it in minutes.

QB1 works like this -- fans watching a game, using their own computer playbox, try to guess correctly what play will be called. There are 20 play selections -- 14 pass and six run -- and you have until the time the ball is snapped to make your decision. Your guess can be as basic as run or pass, or you can be more specific, guessing left or right, short or deep on passes, for instance. The more specific your guess, the more points you can score (but your risk of being penalized increases).

You can play the game at home by yourself, compete against a friend or go to a bar or hotel and compete against several people. This satellite-transmitted invention allows you, in fact, to compete against folks all across the country. For once, you can definitively prove that Californians might diet better, but they don't know a fly pattern from alfalfa sprouts.

QB1 comes from NTN Communications, Inc., a Carlsbad, Calif.-based company whose founders include Don Klosterman, the longtime general manager of the Los Angeles Rams. Klosterman enlisted Don Shula, Bill Walsh and Hank Stram as consultants in developing QB1.

When NTN monitors a game, it can provide updated scores of all QB1 players after each play and give you updated statistics of each team's play-calling tendencies. An NTN official scores the game and determines after each play the correct play selection.

This year, the company is introducing QB1 at selected Hilton Hotels during Monday night telecasts. Next year, NTN will market the game in "group environments" -- hotels, bars, restaurants, college campuses, et al. -- before making it available for home use in 1987.

QB1's greatest appeal is how it draws fans into the game, allowing us to guess along with the quarterback or coach. And because we're competing against each other, we'll keep watching a 33-0 game until the end. It's a great tavern game -- perfectly fitted for large-screen TV and a dozen or so competitors drinking, play-calling and taunting each other.

But like most vice-filled pleasure, there is a price to pay. In the end, QB1, like gambling, perverts the sports-viewing experience. When making a wager on a game, the gambler worries about the final point spread or total number of points scored; whoever wins or loses the game becomes academic. Similarly, QB1 players are so intent on seeing if teams run or pass each time that they lose sight of the result of each play and how the game is flowing. QB1, like gambling, presents a tunnel vision of the game.

That's only natural, however, because QB1, in one way or another, is going to become a wagering recreation.

WTOP-1500, radio home of the Bullets and the Capitals, has added an intriguing feature to its sports schedule -- occasional broadcasts of other NBA and NHL games on nights when both Washington teams are idle.

Holland Cooke, WTOP's program director, has lined up eight NBA games and hopes to broadcast up to six NHL games, mostly on Wednesdays and always involving teams from the Bullets' and Capitals' divisions.

"Any Bullets fan will be very cognizant of the 76ers and Knicks. Any Caps fan will always be looking over the shoulder to the Islanders and Flyers," Cooke said. "There's a demand for this. We think there's enough interest in the NBA and NHL, and it gives us a chance to throw up in the sky one more option all over the East."

In every case, WTOP's 50,000-watt signal will pick up the home team's broadcasts. With several Celtics games scheduled, Washingtonians will get a better chance to hear legendary Boston sportscaster Johnny Most.

Cooke also points out that with the large number of people in this area whose roots are elsewhere, the broadcasts will act as "kind of a postcard from home."

As part of the tax-overhaul bill passed by the House last week, there will be a 10 percent excise tax imposed on Olympic broadcast rights fees, to establish a U.S. Olympic Committee trust fund. But according to one local attorney, that doesn't mean the networks necessarily will have to pay more to televise the Olympics, as network officials predicted last week.

"The legislation should have no effect, bottom line, on the cost to the radio or television network or the amounts received by the organizing group," said Philip R. Hochberg, who specializes in communications law. " . . . The excise tax is to be used as a setoff against income tax paid by the networks."

Since the excise tax is deductible, the networks actually could benefit from the new legislation. Hochberg said "it might amount to a windfall for the networks" if the national organizing group hosting the Olympics does not take the 10 percent tax into account when setting its fees.