In my high school days one of my main hobbies was collectible card games, particularly Magic: The Gathering. My friends got me into it and we often got into huge card battles. It gets crazy when more than two people are playing. Like with video games it was an expensive hobby since I had to buy several packs to get any good cards to work with. Nowadays I don't play very much and usually only with my brother who was also into for a while.
There was also a brief time I played the Pokemon Collectible Card game. It was a nice diversion from the video game but I prefer playing the video game by far.