They are generally fun, and invoivle physical activities, which make it more competitive and enjoyable. This webpage will name some sports and the basic contents of it (I don't play many sports, I just don't know what else to do.)
Basketball is a team sport, with 5 people on one team. It is a 5v5, where you strategize and pass the ball to confuse the defence then score. To score, you shoot the ball in the basket. If it goes in, you get points. Whichever team to score the most points in the time given wins.
Soccer is also a team sport, where instead of using your hands to pass and score, you use your feet. The soccer field is large. There are certain positions people go, like defenders, goalies, attackers, and etc. The team to score the most goals in the time given wins.
Tennis is a one on one or two on two sport, where you serve the ball, then you hit it and return it to the other side of the court. If the other person can not return it, or if the other person hits it out, then you get a point. If you win one point, it is worth 15 points. If you win 2, 30 points, if you win 3, then 40 points. And after that, if you win another, it is game for you. You have one game. The first person to score 6 games wins a set. Depending on the number of sets played, it can be first to 2 sets, or first to 3.
Nothing really special, you just run. The distance varies however. If it is short distance, then you use all your energy to bolt to the finish line. If it is long distance, you take your time, and conserve energy.
You get into teams, (the number of people on a team can vary) and each start with a certain amount of balls. Your goal is to try to dodge the balls others throw, but hit others with the balls you throw. If you get hit by a ball, you are out. Whichever team has the last person/s standing wins. If you catch the ball, then the person who threw it gets out.