Impulse Trigger

Play with the Top card of you library revealed.
You may exile an instant, sorcery, or land from
the top of your library. When you exile a card this
way, Exile cards from the top of your library until
you reveal a card of the same type, you mast cast
it without paying it's mana cost.
you may play cards exiled with Impulse Trigger
until the end of the turn.