By all reasonable measures, motorcycles are practical vehicles. They cost less than cars, require relatively little fuel, and offer much-needed reprieve from urban gridlock. But since the mid-20th Century, when motorcycle gangs became popular and movies like Easy Rider bound ideas of freedom and rebellion together on the the wheels of custom choppers, the motorcycle idea has loomed gigantic in the cultural imagination. The Mama Tried Motorcycle Show, an event launched by Harley Davidson, honors that idea by bringing together mechanical hobbyists, race fans and the cabal of willful outsiders who form the grassroots core of the show.We were there for Flat Out Friday on February 23rd, which serves as the thundering opening ceremony of the Milwaukee event as more than 10,000 fans watched from seats surrounding the track. Here, a few of the highlights.