Hat Day
Hat Day falls on January 15, marking a garment that was compulsory for centuries and then vanished from ordinary life within about a decade.
January 15
3 holidays
Personal Firewall Day
Personal Firewall Day falls on January 15, and the threat it was created for has largely been solved, while the one that replaced it ignores firewalls entirely.
Strawberry Ice Cream Day
Strawberry Ice Cream Day falls on January 15, and strawberry is the hardest of the three classic flavors to make well, for a specific chemical reason.