There are several holidays in October, including national and international observances, religious holidays, and fun holidays. Here are some of the holidays in October from the search results:

• National Energy Geek Day (October 1st)
• National Mad Hatter Day (October 1st)
• World Smile Day (first Friday of October)
• National Kale Day (first Wednesday of October)
• Columbus Day/Indigenous Peoples Day (second Monday of October)
• National Bosss Day (October 17th)
• Sweetest Day (third Saturday of October)
• Halloween (October 31st)

In addition to these holidays, there are also several religious holidays observed in October, such as Navaratri, a Hindu festival that celebrates the Mother Goddess Durga.