If you want to stay fit you can do crunches

[hax]

I have found that if you want to stay fit, you can do crunches (I ususally do about 30 crunches).

Then after that I am not sure what these are called, but it is like a crunch, but when you go up with your back and neck, you bring your knees towards your head, after about 15 of these you will really feel the burn!

[surfville10]

There are lots of things you can do as form of exercise. But I think cardio-exercise such as walking, running an even dancing are good ones. Maybe you can do these at least 15-30 minutes because study says that calories starts to be burned after 15 minutes.

[arcel]

The Best Exercise you can do is doing a BOXING routine from hitting the mitts, doing the speed ball, doing the heavy bag, the little sparring and etc.
You are training like a gladiator that will go to battle. In Boxing you need to be ready using your mind and body. That is the reason why they call it the sweet science the art of hitting and not getting hit back.

[Andy]

I think riding a bike. You get a lot of exercise. you get out of the house, and you can see different places on your ride.

[guru]

Well all forms of exercise are good depends on what muscle you're defining. For instance, if you'll trim your abs, crunches and sit ups will be best. However, if the biceps and triceps maybe you should do some weight lifting.

[trekjunkie]

I find that the best exercises are the ones that cause you to use your own body weight to build your strength such as boxing and some forms of dance. This gives you just enough weight to work with because it's not too much that it will hurt you or cause you to sprain yourself, and it's not too little to where it wouldn't be effective.

[djschwab]

The best exercise as far as an all around workout is swimming laps. This will give you the cardio benefits as well as help tone your muscles. It is very low impact and not hard on your joints as are some other forms of exercise can be.

[surfzone]

Swimming is a good exercise! However, of you don't have the facility, I suggest that you do jogging or running instead. These activities doesn't require any gadgets. Also, those are also cardio exercises which will help burn fats and excess calories.