Over the last two years I have come across about 10 playing cards on sidewalks and roads all around the world. My first couple were found on a very distinct night when a house party was cancelled and a group of us had to walk around and drink in miscellaneous parks... there is a picture of a couple of us in a gutter from that evening as well. I always carry the Jack of Hearts I found that night. The reasons are that: my favorite number is 11 ( Jack card comes after 10), hearts are universal, and I like boys ( Jack).
It's strange how many obscure/interesting items you can find during walks by just paying some more attention. I actually heard from someone that playing cards were very common to find. I'm slowly making my way to 52.
Take a closer look and learn how to play poker.
( Sorry about the strange smiling child in the picture, I really liked the 11 of hearts in the background )