General fact: 42 is the number of museums in Amsterdam (Netherlands has the highest concentration of museums in the world).
Mathematical fact: 42 is the product of the first three terms of Sylvester's sequence; like the first five such numbers it is also a primary pseudoperfect number.
Trivia: 42 is the number of gallons that one barrel of petroleum holds.
Historical date: February 11th is the day in 1953 that President Dwight Eisenhower refuses a clemency appeal for Ethel and Julius Rosenberg.