Toners: Let Us Sing Into The Mouths Of One Another

Using a paper towel tube, two players position the tube so it covers each of their mouths.
On the third player's signal, the two players adjoined by a tube intone a tone. Their goal is to stop and start the tone as many times as possible before the get out of sync. If one of them stops the tone for longer than a second before the other stops, then their turn is over.
The non-intoning player is responsible for counting the number of stops and for judging when the turn should end. Players are awarded one point for each successful start and stop. Play rotates so that the non-intoning player becomes one of the two intoning players in a new round of play.
The player with the most points after a predetermined number of rounds wins.