In 1938, Pappy Hoel and the Jackpine Gypsie motorcycle club, decided to have an annual rally the the small town (pop. 6,400) of Sturgis, South Dakota. Every August since then, motorcycle enthusiasts have gathered until it has become a huge event, attracting almost half a million bikers from all 50 USA states and quite a few from Canada and other countries.
While some folks will be rowdy, most will just enjoy the extensive schedule of events, as well as get together with old and new friends.
My daughter and son-in-law went two years ago, combining the rally with an extensive cross-country motorcycle trip. They had a good time and were able to visit many western landmarks that they had not seen before. While they are happy they went, it is not something they want to do regularly, maybe again in a few years.