New York ? Turn off the TV and go outside! Kids hear that from their parents all the time. Now, improbably, they’ll hear it from a TV network.

This fall, the Nickelodeon network will go off the air for three hours one Saturday and urge its young viewers to play instead.

The turn-off is planned for Oct. 2 at 11 a.m., when Nickelodeon typically has about 1.5 million viewers ages 6 to 11. During those hours, Nick will show a graphic saying it’s time to go outside.

“They’re not doing as much after-school play as they used to,” network president Cyma Zarghami said, “so we wanted to make sure they know it’s important.”

She’s certainly aware of the grand irony of this coming from a network that made it possible for kids to spend hours on end staring vacantly at the tube. But she said studies had shown children weren’t watching much more television than they did 15 years ago.

“We don’t have control over how much they watch television,” she said.

Nick probably won’t lose much advertising revenue during the stunt; companies will be compensated by having commercials run at different times, she said. Nick estimates it’s spending some $10 million on its “Let’s just play” campaign.

When Nick comes back on the air that day at 2 p.m., it will air a live music and sports special that encourages viewers to stay healthy and active.

During its campaign, Nick is also sponsoring play days in 10 U.S. cities, inviting families to parties at parks.

If it’s a success, might a couple of hours off per week become a regular part of Nickelodeon’s schedule?

“Our cable operators and our advertisers might have a little trouble with that,” Zarghami said.