The grassroots fitness initiative the November Project in Boston, which organizes workouts using social media, has begun an offshoot in Madison, Wis., and has inspired other groups, such as ParkRun in Chicago and Houston, NYC Bridge Runners and It Burns Joe Fitness in Denver. Fitness-gear companies are eager to partner with the group, but November Project organizers say a grassroots effort cannot look like a corporation and the group will never charge for its workouts.