October 4: International Holiday In Space Day, National Day of No National Holidays (Botswana), International Zombie appreciation day
- 1582- The Gregorian Calendar is implemented, skipping straight from October 4 to October 15. This new calendar replaced the Julian Calendar, and was the final straw in a massive flame war between Julius Caesar and Pope Gregory the Great.
- 1846 - Smithsonian Institution opens its first Air and Space Museum. Due to the limited technology of the day, the exhibits consist of a kite, a feather, and a weird-shaped greenish rock that "looks kinda like it coulda come from space, or som'thin".
- 1985 - The comic strip Fred Basset quixotically debuts in American newspapers.
- 1991 - Leo Fender, inventor of the electric guitar, passes away. His death is marked by a minute of silent rockin' out on the air guitar (pictured).