According to the search results, there are several holidays and observances celebrated on September 23. Some of them are:

• National Family Day
• Celebrate Bisexuality Day
• Education Technology Day
• Innergize Day
• International Day of Sign Languages
• National Seat Check Saturday
• National Snack Stick Day
• Redhead Appreciation Day
• Restless Legs Awareness Day
• Autumnal Equinox (First Day of Autumn)

It is important to note that some of these holidays are celebrated annually, while others may be observed only in certain years.