Now this is useful. It’s also funny, geeky and more than a little silly. xkcd presents a useful guide to metric measurements:
As usual, click the image to see the whole thing.
Leaving aside the geeky silliness, this is actually a good idea – you’re much more likely to understand measurements if you have a feel for them, which is why even generally quite metricated Brits of a certain age still think of their height in feet and inches and their weight in those odd stone thingies. But never mind that, just enjoy the silliness.
 Which is pretty much how I like to think of myself, so I feel a certain affinity
 The last entry in the speed list is a particularly fine example of that
 Actually, at my age, I think I might need to start being less certain about it