Halloween

Halloween is a day of observation that is normally celebrated by humans, usually in the form of people going about in costumes doing trick-or-treating. In the cartoon show universe, it is also the day of Jokey's birthday, which the Smurfs celebrate by letting him offer all his fellow Smurfs his "surprises" by going through the alphabet of Smurf names, as it is Gargamel's birthday, a fact that he greatly despises. Hogatha the witch calls Halloween her favorite day of the year because she gets to scare little children. On one particular Halloween in the episode "All Hallows' Eve", Lazy was accidentally turned red by Mother Nature who was using her red magic wand to turn the leaves of the Smurf Forest red, and was unable to change Lazy back without the additional help of Father Time, who used his powers over time as well as Mother Nature's magic wands to restore Lazy's original appearance.

Because that day is reserved for celebrating Jokey's birthday, a similar day of observation called Spook-A-Smurf Eve is held presumably around that same time period.

In the EMPATH: The Luckiest Smurf story series, due to his particular beliefs, Tapper refuses to celebrate either Halloween or Spook-A-Smurf Eve, though he will take part in Jokey's birthday celebration.