General fact: 2311 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 2311 is an uninteresting number.
Trivia: 2311 is an unremarkable number.
Historical date: April 29th is the day in 1882 that the "Elektromote" – forerunner of the trolleybus – is tested by Ernst Werner von Siemens in Berlin.