Einstein was a gifted musician and played the violin. He even said that if he hadn't been a physicist, he would have liked to have been a musician.
He was offered the presidency of Israel in 1952, but he declined, stating that he had "neither the natural ability nor the experience to deal with human affairs.
Einstein's famous equation, E=mc², was not originally written as such. In fact, it was first written as m=E/c², but later rearranged for clarity.
He was once offered the position of being the King of Albania, but he declined. It is unclear if this offer was genuine or simply a hoax.
Einstein was a pacifist and opposed the use of nuclear weapons. He urged President Roosevelt to consider the ethical implications of creating such a weapon, but ultimately the decision was made to drop the atomic bombs on Japan.
He had a unique sense of humor and loved to play practical jokes on his friends and colleagues. For example, he once convinced his friend, physicist Paul Ehrenfest, to participate in a prank that involved Einstein pretending to be his own chauffeur.
Einstein's brain was preserved for scientific study after his death, and it was found to have several unique features, including an unusually high number of glial cells, which are associated with information processing and communication in the brain.