Thinking of the bonehead plot to attack the UFC event:
Since you all are into history. John Wilkes Booth was a nationally known actor so it was not unusual for him to be at a play. He was part of a bigger plot to kill Lincoln, VP Johnson, and Secy of State Seward that night. Wilkes was successful, Seward survived, and the guy assigned to Johnson lost his nerve. Ulysses S Grant also was supposed to be at the play that night and was going to be targeted but his plans changed and he did not attend. It was a plot to throw the Union into disarray -- but by this point Lee had surrendered and the South's capital Richmond was in Union hands, so boneheaded.
The other interesting tidbit is an armed policeman was assigned to stand guard over the entrance to the theater box Lincoln was in. He left his post, reasons vary but one theory was so he could go to a bar next door and get a drink. When Booth showed up the way to Lincoln was wide open. The policeman was investigated but never punished and stayed on the police force.