Make them watch their favourite sport
Take them out for games and sports. Enroll them in some course related to their interest.
Ask them if they have any interests or something and just let them do their thing under non existent supervision. Place urself in their shoes.
If possible go out in a park, play any sport
Video games are normally a sure way to entertain any teen.
Try to find them with their hobbies
Give them mobile phone that's it! Modern problem required morden solutions.
Mobiles, any movie if everyone is able to pick one!