It was a 240-mile, 29 1/2 hour, people-powered tricycle ride from Flint to Mackinaw City . Then, it was a swim from St. Ignace to Mackinac Island , with a 50-foot barge in tow. It concluded with Mr. B and His Band performing at the Grand Hotel as part of the annual Labor Day Jazz Weekend . Renowned Ann Arbor boogie-woogie pianist Mr. B, Mark Braun, stopped by the WEMU studio's early labor day morning to share the experience and discuss what the charitable ' Joybox Express-Sprint 4 Flint ' will