In Monty Python's the Meaning of Life, the machine that goes "ping" is a device that doctors use to determine that the baby they're delivering is alive.
It is also the most expensive machine in the whole hospital.
"Aah! I see you have the machine that goes ping. This is my favourite. You see, we lease this back from the company we sold it to, and that way, it comes under the monthly current budget and not the capital account."