A game which requires steps, a football, and several young children so eager to play with the big boys that they are willing to approach slowly down some steps towards men kicking footballs at them. Boys (never girls) started at the top step, chanting "we are space-invaders". Once hit by the footballs, you moved onto the next step down - an improvisation from the strict format of the arcade game, allowing for more bruises. Now you must run faster, and are more likely to be hit by a ball this is travelling at a higher speed. Once you reach the ground floor, by which point you should be screaming "we are space invaders", you were relieved, and could move to the top step again. The lure of watching your friends getting hit with footballs was always too much to resist. No-one ever really though to simply stand aside and watch the game. Apart from the bemused teachers.