I think Swimming is the best game to lose weight as well as to maintain body. It also now a one of the most popular game in the world.
Top 5 Sports for Fast Weight Loss http://www.itrainharder.com/top-5-sports-for-fast-weight-loss-and-super-fitness/
Have some run in every morning is the best i think. You don't have to spend some money to lose your weight by running.
I used to play badminton in every morning. But i dont think it's good exercise to loose your weight, try to walk or jog. Both are full body exercises.
Running burns about 450 calories every 30 minutes if you run at a mile every 8 minutes. Rock Climbing will burn around 371 calories per half hour. Swimming burns about 360 calories per hour depending on the stroke and intensity. Cycling can burn between 300-400 calories per half hour depending on speed and effort.