Im working on a trading card game of my own design, its pretty cool right now. It borrows heavily from Yu-Gi-Oh but with much more strategy involved.
You still have the same old monster/spell/trap arrangement. It works well so i didnt want to mess with it. Here is how Enternity TCG works
Its pretty loose, every turn you can draw 1 card, summon 1 monster(its not limited by level yet), and attack once with every monster. but, if you dont summon or draw, they will stack up, allowing you to wait and then summon a ton.
summoning -
when you summon a monster or a spell/trap card, you choose to summon it in the front or back line. for every monster in the front line, every monster in the back line gains + 10 defense.
spell and trap cards can be destroyed if you dont have any monsters.
Attack -
when you attack with a monster, the attack goes through this sequence:
defense of the attacked monster is subtracted from the attack damage
backline and spell effects are taken into account
damage is delt
left over comes out of the enemie's lifepoints.
instead of comparison, damage is delt to each cards hitpoints, when a cards hitpoints run out, it dies and the excess damage is done to your lifepoints

missions-
in this game, you choose a side at the start. Your side determines what cards you can get and what missions you can do. A mission is simple, one side has to complete an objective and the other side has to stop them by finding their soldiers and dueling them. When a side completes a mission, its points will go up. At the end of the week when the points are talleyed, the winning side will get a bonus of some sort.

I have the basic duel functions complete, now i have to add cards and stuff.