When we talk to our grandchildren about the the time between March 3, 2011 and September 3, 2011, only one event will define the period: The brief, but passionate and tender best friendship that existed between Jimmy Fallon and Stephen Colbert. Even Arianna had a significant stake in seeing that Stephen Colbert and Jimmy Fallon's flirtation as best friends was a thing of beauty.But just as all good things must come to an end, Colbert and Fallon's status as BFFFSM (Best Friends Forever For Six Months) ended last week.