Timekoin is a open source, peer to peer digital currency that is unique in the crypto world. Timekoin is unique in that it separates transaction processing and currency creation. Instead, each block is a 5 minute window where transactions are processed. Currency generation is handled independently and based on your time on the peer to peer network. The longer you are online, the more currency you generate. This model makes generation energy efficient with a low end hardware requirement. Check out more, http://timekoin.org/index.php?option=com_content&view=article&id=53&Itemid=56
Forum thread for this Timekoin gateway: http://forums.timekoin.org/viewtopic.php?f=12&t=9663