My favorite card has to be Horizon Chimera. This new card took the place of Twincast and the other 2 mana copy spells because of the simplicity of the card and its power. I've never had anyone ask "so I'm drawing a card, do I gain a life" when it comes to the Chimera. Also, the feeling you get from flashing in a 3/2 flier when they least expect it is great.
I used the Chimera in conjunction with Archangel of Thune and Fathom Mage to make a return to standard for a short while. The look on someone's face when they realize what is happening is priceless.
As for explanations, maybe this will help: A baby cannot be born wearing clothes, even if the clothes were bought for it at the same time it was born. It has to already have been born, then given the clothes.