With their embedded micro-controller and serial EEPROM combination, today's 'smart cards' have many more uses than dumb cards which merely have a magnetic stripe.

Smart cards are already used for pay TV set-top box and mobile phone authorisation but these applications really only scratch the surface of their potential.

You could use them to build your own personalised security access system, for example, or to provide a 'plug-in brain and memory' for small robots and digitally controlled machines. Or to provide plug-in schedules for automatic control of a model railway, or pointing data for a computer-positioned telescope, or whatever...

Using smart cards for your own applications is now quite feasible because blank smart cards and matching 'sockets' are now available at quite reasonable cost.