Hug-A-Smurf Day is a day of observance for the Smurfs that takes place in the cartoon show episode "A Hug For Grouchy". It is a day set aside for Smurfs to express their feelings for each other through hugs. Grouchy hates this day because he hates sharing his feelings with any Smurf, and he particularly hates hugs. The other Smurfs, either for wanting Grouchy to be more open about himself or out of plain disrespect for his feelings, try to accost him at every turn by ambushing him with a hug, but he usually avoids them.
In the episode, a fairy who was struck by Chlorhydris' Ice Wand was using the wand to turn the Smurfs into emotionless zombies on that day, and Papa Smurf finds out that the Ice Wand's power can only be broken if the holder of the wand is given a great big hug by a confirmed grouch. Grouchy, realizing that he is a confirmed grouch, refuses to do so, until Papa Smurf warns him that if he does not give the holder of the Ice Wand a hug, all his fellow Smurfs will remain without feelings forever by sunset.
When Papa Smurf was struck by the Ice Wand and the fairy was distracted by trying to use its power on Baby Smurf without any success, Grouchy bravely reached out and gave the fairy a hug, which freed her from the power of the wand in addition to everyone else struck by the wand. By the end of the episode, the Smurfs finally ambushed Grouchy with a great big hug that he couldn't escape from.