General fact: 42 is the number of kilometers in a marathon.
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 244 that Emperor Gordian III is murdered by mutinous soldiers in Zaitha (Mesopotamia).