How Do You Tag?

I assume you want to know how to play the game of tag. This simple game has done away with little children's boredom since decades. Its beauty lies in its simplicity. Here's how you can indulge in a little fun with your friends.

Firstly, determine who will be 'it', that is, that individual who will chase everyone else. Then, determine the borders of the game, a certain distance beyond which no one can run. Whoever does has to become 'it'. The un 'it' persons ought to be granted a head start of a few seconds before the 'it' person. If the 'it' individual succeeds in touching any one else, then that person become 'it' and then he has to go through the entire procedure.  Basically every one's else's aim here is not to get caught.