An intense and moving game for two people. One to stand with their back towards the other, who would recite the following whilst rythmically punching him in the back:

'Mummy's dying, Baby crying
Concentration!
Concentration!
Feel the knife (punch) in your back, feel the blood dripping down (mimicked with fingers)
Concentration!
Concentration!'

This could carry on for up to about half an hour with varying additional verses. By the end your back would be numb and covered in bruises, but more significantly, your soul would be damaged beyond repair.

There was an additional twist: After four or five verses, when you sense your subjects mental defences have been suitably weakened, suddenly switch to:

"You're on top of a tall building... AND YOU FALL OFF!!"

This line was accompanied by a violent forward shove. If, as was hoped, the victim's imagination had momentarily gotten the better of them, this sudden image would induce, at least a two-second show of shrieking and thrashing about on the ground, and, at best, a lifelong struggle with depression and psychosis.