Okay, my freinds and I made out own card game awhile back, we called it Monster Card Battle. It was a pretty cool game. We took elements from Pokemon, Yugioh, Magic the Gathering and a few other games to create it. Heres how it worked:

There were __ different elements : Dark, Light, Metal, Water, Thunder, Grass, Rock, Fire, Wind Undead and Unknown. You could use any monster no matter what your Monster Tamers' specialty was, but if any monsters where not of the type the Monster Tamers' specialty was, you couldn't use their effects. Also, you couldn't use Unknown monsters unless your tamers specialty was Unknown.
Each Monster Tamer has HP and MP. Each Monster has HP. At the beggining of each turn, your Tamer regains its MP. To summon a monster, you had to pay a certain amount of MP, same thing when you used effects. You can summon as much as you want, but the monsters you summoned get 'Summoning Sickness', so they can't attack or use effects that turn. The game is over when your Monster Tamers' HP runs out.

I was thinking about turning this into a game, but I wondered...do you just buy the monster cards and throw them in your deck, or do you but blank cards, go out into the wild, and battle wild monsters. Once the monster is weak, you throw a blank card at it, and you may capture it? What do you guys think? Any suggestions?