"Ey kids, the weather is too nice to hang out indoor. Out with you!" So, or something like that, it always sounds, when Mom has realized that something must be done against inertia and lack of exercise. Simple outdoor toys could increase the consent and make it attractive to follow Mom´s well-intentioned command. These include boccia balls, frisbees, ropes, swings, trampolines, badminton rackets, sacks, balls of all kinds, etc.. Without equipment, yoga, tai chi, hide & seek, tree climbing and activities like that could work. Daddy should have mowed the lawn previously.