I hear a chorus of "What's a Third Order Dominican?" The Benedictines and some other orders call their Third Order laypeople "Oblates."
A good friend, Julie Olson, and some others have felt called to become Third Order Dominicans in the Twin Cities area. They will remain as laypeople, some single, some married, but will make commitments as Dominicans with an obligation to pursue a prayer life similar to that of fully professed Dominicans. Some Dominican Saints you might recognize are St. Dominic, St. Catherine of Siena, St. Louis de Montfort, Blessed Pier Giorgio Frassati and Blessed Margaret of Castello.
Julie has set up a blog for the new group, Dominican Minnesota, where you can visit and find out more about the group's plans.