Well, it's a ccg/tcg based on the Adventure Time episode by the same name.
It's important to note that it's a game within the series, so Finn and Jake won't be on the cards, but rather fictional characters within the fiction.
(an expansion let's you play AS the Adventure Time characters which grants a small special rule depending on which character you choose)
You and your opponent each have four opposing lanes and a deck of cards.
Each lane is represented by a type of landscape which also dictates which cards you can play. If you only have Cornfields you can only play cornfield type cards (and rainbow/multicolor cards).
But if you have only 1 cornfield you can only play cornfield cards with a value of 1.
Basically you play creature cards to defend and attack in each lane. opposing creatures does damage to each other simultaneously.
If a creature attacks an undefended lane the "player" takes the damage instead. Reducing the opponent from 25 HP to zero is the object of the game.
In addition to creatures you have permanent buildings that grants an effect to the lane they've been played on and you have your one-use spells.
And that's basically it. There's enough strategy to not be random, and both the rules and the cards are simple enough to play with non-geeks like girlfriends and family.
I played it with my brother who hates fun and he just couldn't stop playing!