I was thinking back and the first time I sat down and played was when my friend turned me onto the game. I was hanging out at his house using his account. He had to go to work but insisted I stayed behind and played more if I wanted to. I ended up sitting there and playing 9 hours straight.
From that point on, we (about 4 to 6 of us) would gather over someones house and play together. It was quite fun. We did Raids and such and I got hooked.