Exile the top three cards of your library. Until end of turn, you may play cards exiled this way. (If you cast a spell this way, you still pay its costs. You can play a land this way only if you have an available land play remaining.)
7/18/2014 The cards are exiled face up.
7/18/2014 Playing a card this way follows the normal rules for playing the card. You must pay its costs, and you must follow all applicable timing rules. For example, if one of the cards is a creature card, you can cast that card only during your main phase while the stack is empty.
7/18/2014 Under normal circumstances, you can play a land card exiled with Act on Impulse only if you haven’t played a land yet that turn.
7/18/2014 Any cards you don’t play will remain exiled.