Players may attack either of their opponents with creatures or spells. You can only target your teammate with cards that can target an opponent. We play for fun. If you want to playtest tournament decks, there is usually someone who will accomodate you. Play your tournament decks during regular group games is cause for ganging up.
Nobody likes to be direct damaged to death.
You won't either once we get through with you, flame boy. Rules controversies are settled by majority vote. And no, we're not impressed by your DCI Level V Judge certification. New players are always welcome. If you're just starting out, come on down.