Remember the Chia Pet? Jamie Wiek created the business-card equivalent. The Growing Business Card has all your usual phone/e-mail/address information, of course, with one extra feature: plant life. After dipping the card in water, some alfalfa or cress will be popping out of the top within a few days.
The simple instructions for getting the card to grow adorn (fill dish with water, dip card in) one side of the card, encouraging your contacts to actually pull out your card after you give it to them, while emphasizing your company's green slant. Just don't call them green cards.