I occasionally pass out cards to slot players in Vegas casinos – sit next to them and play and chat them up.
I have done this in airports also – usually to poker players, they can often be recognised by looks. I just walk up to them and ask them if they play poker, if yes I’ll start talking.
If you wear a t-shirt with your site’s name, people will often chat you up and you can hand out a card. Happened quite a few time while shopping.
More often than not, having made personal contact, these folks will come and check things out and contact me for recommendations…