Was on a long motorcycle trip with a few friends. We had left our home in the US and were traversing Canada which, of course, uses the metric system, unlike the US.

As we passed one sign, it said something to effect of "Dawson City 1500km", which I remarked on over the radio as it was a nice round number (and, of course, quite some distance, and a large number you're unlikely to see on a road sign in the US due in part to the greater length of the mile).

My buddy chimed in "ONE POINT FIVE MEGAMETERS"

We laugh about it to this day.

Yes, megameter, or Mm, as opposed to millimeter, mm.