Here's a light-hearted challenge for anyone with nothing better to do. Now that metrication is, if not standard, pretty widespread on the eastern side of the Atlantic, it's time some old songs were brought up to date. Irish songs could even include reference to euros, but the UK will have to make to do with decimalisation. I'll suggest a few lines or titles:

Never let a sailor boy 2.5 centimetres above your knee.

I'm 804 kilometres from my home.

Keep your hand on your half-pee (not the exact amount, I know, but the nearest available coin of the realm).

And I will come again, my love, though 'twere 16,000 kilometres.

Over to you,

Marje