Mark Twain Commemorative Coin Act Signed Into LawMark Twain Commemorative Coin Act Signed Into Law(Washington D.C.) -- President Barack Obama signed the Mark Twain Commemorative Coin Act into law yesterday, which will benefit four Mark Twain sites including his boyhood home in Hannibal, Missouri.Townsquare Media Quincy-HannibalTownsquare Media Quincy-Hannibal