The design of the contact card has stayed relatively standard over the years for simplicity's sake, but the Clark&Kent business cards are breaking the conventional commercial mould.
Ad agency Clark&Kent houses their headquarters in a phone booth in New York. In order to highlight this abnormality, their business cards are modelled after their odd homebase, as pop-up phone booths themselves. Anyone handed this card may be confused at the design at first, but will quickly learn the backstory behind it -- effectively engraining the company into their memory.
In this case, the business card is not only a conversation starter, but also serves as an important keepsake that can stand out amongst less impressive contacts.