The 150-year celebration at Angels Camp, the Calaveras County mining town, where Twain first encountered the frog-jumping story. Details in an article in the LA Times available at

http://www.latimes.com/entertainment/great-reads/la-et-c1-mark-twain-california-20150514-story.html#page=1

Enjoy, 
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Paul P. Reuben
http://web.csustan.edu/english/reuben/home.htm