I cleaned this up a bit. I don't think they're that funny.
Sic Semper tyrannis is a Latin phrase meaning "thus ever (or always) to tyrants." Recommended by George Mason to the Virginia Convention in 1776, the phrase is attributed to Marcus Junius Brutus at the assassination of Julius Caesar. It is sometimes mistranslated as "Death to tyrants."
According to some witnesses and an excerpt from John Wilkes Booth's diary, he is said to have shouted the phrase after shooting United States President Abraham Lincoln in 1865. Coincidentally, both his father and his brother's names were Junius Brutus. Timothy McVeigh was wearing a T-shirt with this phrase and a picture of Lincoln on it when he was arrested on April 19, 1995, the day of the Oklahoma City Bombing.