I went to school in a few towns, but I only recall playing this in Armidale, NSW.

Everyone runs across the field together, while one person tries to tag as many people as they can. If you're tagged then you are also a tagger in the next round. Repeat until one person is left, who starts the next game.

We were actually banned from playing this because we preferred to tackle instead of tagging. Nobody got seriously hurt, but the teachers thought it was only a matter of time.