The "Q" is the leader responsible for the Outcome.
The origin of the term came from the workout group that F3 was born out of, where the leader was known as the Qrusader in charge. Every Workout is led by a Q, who is responsible for the planning and success of that day's Workout. In addition, each Event (Workout/Coffeteria/CSAUP etc.) has a Q responsible for the planning and coordination of its outcome.
In Kalamazoo, Iverson is the Q for KindleBerger, and in Grand Rapids, Ridgecrest is the Q for Safari @ John Ball. These men are responsible for ensuring a Q is in place for every given workout, and are responsible for being the Workout Q when needed.
As F3 is an organization made of leaders, not an organization with leaders, it is expected that all men become Q's in and out of F3. It may take you a number of workouts before your VQ (Virgin Q: first time leading a Workout), but growth toward that is expected. Becoming a part of F3 will prepare you to be effective Q in all aspects of life for planned and unplanned circumstances.
Integral to F3's mission is to invigorate male leadership. F3 has a QSource that is a resource for leadership. It lays out the G3L principles: GET RIGHT, LIVE RIGHT, LEAD RIGHT, AND LEAVE RIGHT. Visit the QSource link above for a more in depth exploration and additional resources.