The Pigpen code (also sometimes called the Freemason's or Rosicrician cipher) is quite easy to catch on to. First you write out the whole alphabet in two grids, as shown:
Each letter is represented by the part of the "pigpen" that surrounds it. If it's the second letter in the box, then it has a dot in the middle.
So an A looks like this:
And a B looks like this:
This is decoded as "LISTEN TO THE WIND".