General fact: 266 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 266 is the Stirling number of the second kind S(8,6).
Trivia: 266 is a boring number.
Historical date: September 22nd is the day in 2003 that David Hempleman-Adams becomes the first person to cross the Atlantic Ocean in an open-air, wicker-basket hot air balloon.