September 23 is not a special day in the sense that it is a widely recognized holiday or event. However, there are several holidays and observances that fall on this day, as well as notable historical events and famous birthdays. Here are some of the things that are special about September 23:

• Holidays and Observances: There are several holidays and observances that fall on September 23, including National Family Day, Celebrate Bisexuality Day, Education Technology Day, Innergize Day, International Day of Sign Languages, and National AFM Day. Other sources list additional holidays and observances, such as National Singles Day, Redhead Appreciation Day, and International Rabbit Day.

• Historical Events: September 23 is the 266th day of the Gregorian calendar, and several notable historical events have occurred on this day. For example, Harvard College held its first commencement exercises on September 23, 1642, and pilot Earle Ovington delivered the first batch of official American airmail on September 23, 1911. In addition, astronomer Johann Gottfried Galle became the first person ever to observe the planet Neptune on September 23, 1846.

• Famous Birthdays: Several famous people were born on September 23, including Augustus Caesar, Bruce Springsteen, and John Coltrane. Other sources list additional famous birthdays, such as Jermaine Dupri and Mary Kay Place.

Overall, while September 23 is not a widely recognized special day, there are several holidays, historical events, and famous birthdays that make it noteworthy.