With me, it usually comes up in conversation. I also get a lot of people commenting on it when they look at my desktop on my laptop (which I bring to school and a bunch of other places), which frequently features lighthouses in the frequent rotation of my photos that it features.

Don't have any sweaters or calendars or anything...but I meet a good number of enthusiasts this way too. I even met an HL enthusiast at one of those YMCA camp type things (school trip) years ago...she was the nurse there. She said she had a lot of older stuff. Not sure what that meant. Referred her to the forums, but I'm not sure if she ever joined - they didn't get great internet up there.