Viewers reacted with both delight and bafflement as ITV was shut down for an hour, with some joking the blackout was "the best thing" they had ever seen on the channel.
As part of a national sports day event called I Am Team GB, ITV encouraged viewers at home to get off their sofa and do some exercise instead of watching television.
Double Olympic champion gymnast Max Whitlock was on hand to pull the lever to switch off all ITV channels in a clip aired just before programming stopped.
Many Britons took up the challenge, tweeting their activities during the hour.
One sports fan revealed he was going for a run, writing on the social networking site: "Great and brave idea #ITV , one day I won't be able to #run but today isn't that day!"
Another revealed she had just been for a "45-minute spin class", adding "good for @itv, let's get moving in whatever way we can".
Plenty of people shared pictures from their exercise-filled hours, but many just made fun of the whole scheme.
Some joked ITV's static screen was top viewing, while some refused to go out and get moving.
"The best thing I've ever seen on ITV," one Twitter user wrote, and another added: "I'm more likely to get out and run when ITV shows programmes."
Another viewer said they would merely choose another channel, adding: "ITV shutting down for an hour to encourage me to exercise is going to be a big workout for my thumb on the remote."
After returning home from Rio with their biggest medals haul in 108 years, many members of Team GB used the event to join members of the public at sporting activities across the country.
Over the bank holiday weekend, hundreds of sports venues and clubs are opening their doors free of charge as part of a collaboration between the National Lottery and ITV.
Max, who joined members of the public for some handball at the Copper Box Arena in London's Olympic Park, said: "I first started gymnastics in Hemel Hempstead at Sapphire School of Gymnastics.
"Knowing how friendly and life-changing clubs like this can be, I'd encourage everyone to get involved in I Am Team GB - the nation's biggest-ever sports day."
Soap enthusiasts were also able to head to the Coronation Street set in Manchester, where Olympic champion cyclist Elinor Barker was taking part in an event on the cobbles.
Other Olympians joining in include rowers Karen Bennett, Katie Greves and Helen Glover, cox Zoe de Toledo, swimmer Jazz Carlin, trampolinist Bryony Page and gymnast Amy Tinkler.