Tag

• Tag is the classic kids' game with a dozen variations. It requires no special equipment, and the rules are easy to learn. It involves a lot of running, so it can make for good cardiovascular exercise. If you get tired of the simple version, try freeze tag, or adding "base" that a player can use to avoid being tagged for a short while.
  
  

Volleyball

• Backyard volleyball is another great exercise game that emphasizes upper-body strength and quick reaction speeds. All you need is a ball and a clothesline that you can stretch between two trees. Optionally, you can create bounds-markers with cones or makeshift flags.
  
  

Soccer

• Soccer is another easy-to-learn game, and it can be played on any size yard. The smaller the yard is, the smaller the goal should be. You can weigh down cardboard boxes for a goal or just mark out a "goal zone" with sticks. Soccer is a good cardiovascular exercise because of the continuous running performed during the game.
  
  

Football

• Football is another game that only requires a ball and boundary markings. You can play touch or tackle, depending on the preferences of the group. The game puts an emphasis on cardiovascular activity, but it also involves upper body strength and careful field positioning.
  
  

Frisbee

• More durable and less expensive than sports balls, Frisbee is a classic game that can be enjoyed with any number of people and even the family pets. If you have enough people, you can even play "Ultimate Frisbee," also called "Ultimate," which is a game similar to basketball and football. The object of the game is to get the Frisbee into the other team's end zone. Players cannot move if they are holding the Frisbee, and a dropped Frisbee results in an instant turnover.