Back when Final Fantasy 8 came out, I got the video game almost immediately and put well over 100 hours into the game by doing everything possible. One of the things I did was I obtained every Triple Triad card in the game and spent many hours playing the triple triad card mini game in FF8.
Final Fantasy VIII never allowed for you to play the TT game with another person, only CPU characters so when I found out that there were actual cards that you could buy, I instantly imported an entire box set from Japan.
Playing the card game with a friend is very fun and addictive. The basic rules of the game are very simple to learn but still require a lot of strategy - you're constantly trying to stay 1 step ahead of your opponent and trying to draw them into traps, just like you would in chess. Although the basic rules are simple to learn, there are more advanced rules that you can play by and although they aren't that hard to learn, they take the strategy to a completely new level. Point is, there's so many different ways to play this so the replay value is incredibly high.
You need 10 cards total to play the game, 5 cards per a person. It's fun and easy to modify and make up your own rules. For example, the playing board is 3 x 3 with a total of 9 spaces but you can increase that for a longer lasting game by creating a playing board of 4 x 4 or even 5 x 5.
These Triple Triad cards are a must for any Final Fantasy fan or collector, you'll see a lot of familiar monsters, even if you've never played FF8 but if you have, you'll recognize all the characters.