I was attending the Iron Man of Gaming 2008 in Dallas when someone threw one of the games on the big screen and a bunch of us watched for a while. Didn't really think much of it at the time other than "neat!" I think I downloaded ESoD not too long afterwards to give it a shot, but didn't keep at it back then.
Couple of years later, I met a friend who was really into it at the time and I mentioned I thought the games and music were neat. They proceeded to show me a bunch of fan creations like some of the popular music videos, general art, and the immense amount of stuff there just is. Eventually we all went to a local convention where they were dressed as Youmu and they introduced me to a group of other fans who were very nice and fun to hang out with.
Ever since then it was a slow incline which reached the final "get into" part when 16 came out on steam and I thought I really ought to sit down and actually play these games.