- Day by Day
- Commemorative Holidays
- Administrative Professionals' Day
- Astronomy Day
- Blog Day
- Clean Out Your Computer Day
- Earth Day
- Google's Birthday
- Inspire Your Heart with Art Day
- International Music Day
- International Tuba Day
- KidsDay
- National Custodial Workers' Day
- National Employee Health & Fitness Day
- National Nutrition Month
- Pinhole Photography Day
- Plan a Solo Vacation Day
- Sports Day
- Video Games Day
- World Hug Day
- World Mental Health Day
- Winnie the Pooh Day
- Inventor’s Day
- Confederate Heroes Day in Texas
- Bob Marley Day
- International Holocaust Remembrance Day
- Imbolc
- National Polar Bear Day
- Burns Supper
- World Leprosy Day
- National Tooth Fairy Day
- Doctor's Day
- Four Chaplains Memorial Day
- Thomas Crapper Day
- National Speak Up and Succeed Day
- National Holidays
- Secular Holidays
- Silly Holidays
- Religious Holidays
- misc. Holidays
Astronomy Day
Astronomy Day occurs on a Saturday between mid-April and mid-May, and is scheduled so as to occur at or just before the first quarter Moon
