Play cards. They're like business cards, but take 30 minutes to make five. Also, they are for handing out to people you want to play with, rather than to people you want to do business with. Well it could be used for both... but I think the normal style business card is a bit boring to give to friends.
Made some of these the other day. Based on an earlier version I designed a few years ago. They're about the size of a finger, but unfold to show other details (eg, email, website, etc).