In a way, living in senior (62+) housing is like living in a college dorm. If you want folks to gather, be sure to serve food. I found a holiday calendar, and then another. And then some info on line. So I collated the information. Turns out the entries were more recognitions and celebrations than holidays, actually.
I color coded them as
- official national or state holidays, such as MLK Day, the 4th of July, Labor Day, Thanksgiving
- religious or folk holidays, such as Christmas, Ramadan, Diwali, Day of the Dead, Halloween
- heros, states, and career and family appreciation days, such as Teacher Appreciation Day, Medical Professionals Appreciation Day, Mother's Day,
- awareness days, such as Cancer Awareness Day, Juvenile Diabetes Awareness Day
- inventions days, such as
- ecology/green days, in which I lumped together environmental, animal, plants and outer space
- the arts and creativity appreciation days, to which I lumped in Shakespeare Day, Wear Pink Day,
- and general foolishness days, like Be Nice to a Grouch Day, Clear Off Your Desk Day, National Hugging Day
But by far, most recognized national "holidays" are food days: Pizza Day, Gourmet Coffee Day, and National Carrotcake Day.