A slot card issued by a slot club, or a membership card in another incentive award program, that is also capable of being used as phone calling card is provided. Free calling time is credited to the member's card account in response to the playing of the slot machine or utilizing the respective service....http://www.google.ca/patents/US6229879?utm_source=gb-gplus-sharePatent US6229879 - Method and apparatus for awarding and redeeming prepaid telephone time
