Duo Security, from some of the Open{BSD,SSH} guys, offers a nice two-factor auth layer that's pluggable into any web or online service; push notifications, SMS,

Duo Security, from some of the Open{BSD,SSH} guys, offers a nice two-factor auth layer that's pluggable into any web or online service; push notifications, SMS, or voice. Similar to Google Authenticator except that Duo isn't limited to Google supported services (although they did take an investment from Google Ventures).