So, we visited St Michael's Mount yesterday, and very enjoyable it was too. And we discovered the most fun you can have there:

  1. Wait for the tide to come in
  2. At the point the causeway starts to get covered in water, get a good vantage point on the hill
  3. With binoculars or a decent telephoto lens, enjoy the sufferings of the those who tried to beat the tide:
Causeway-walkers
The boat across, incidentally, is a grand total of £1.50, and a great ride.