Two Factor Authentication with Sharepoint 2010 and TFS 2012?

I've been tasked with finding a solution for two factor authentication for SharePoint 2012. We have a large number of clients and subcontractors already using the SharePoint and TFS portals with AD authentication. I'm just wondering if anyone has some experience with something like a secondary authentication question (ie: colour of your first car?) tied into the Sharepoint login?

Thanks.