Seth Godin blogged about real estate agent's business cards.

I remembered my manager telling the class to included 'useful information' like calendars or 995(or 911- depending on which country you're in) type numbers on the back of the card just so that owners will have a reason to keep your namecard in their wallets. That doesn't actually work when the whole class takes him up on his advice and all real estate agents' cards come with the panic button numbers, calendar and a pack of tissues.

Seth suggests Moo for something different-a very interesting looking company although I do remember another company based in Barcelona that had better looking templates.

I don't quite agree on the point of steel business cards though- I loved Kevin Mitnick's:

and of course New York's #1 Escort must agree that steel business cards bring in a lot of- business.

Ours is lenticular(or rather mine is- with plans for other agents to use the same namecards later ):