Magic the Gathering

[Aaronock]

With casual play, my group useta be more of an "anything goes" as far as deck building goes. xD
You can also play the very difficult to get into Vintage and Legacy formats I guess. Definitely will want to read up about decks that perform best in those formats but to be honest they are very expensive to get into usually.

You'll want to play Yugioh more for tournaments if you just want to play whatever though. You might be able to get pretty far as long as you play decently and make a semi-coherent deck. x)