During the Hallow's End event, each inn has a Candy Bucket that serves as the start and immediate endpoint of the quest Candy Bucket. Characters are allowed to obtain one from each Candy Bucket, each year.
Unlike many lootable inanimate objects, the interaction mechanism with the Candy Buckets is in the form of the quest. This constrains each character's ability to obtain a to just once per bucket.
Clicking a Candy Bucket offers the option to take a handful of candy; taking the handful of candy completes and gives credit for the quest. There is no separate turn-in, and each candy bucket gives a separate instance of this quest.
These quests have racial restrictions according the player's faction, which prevents doing quests in enemy inns.
There are two pairs of Aldor and Scryer inns, in Shattrath and Shadowmoon Valley. If the quest from one faction's in is completed, the other faction's one from the same zone becomes unavailable (however, you can do Aldor one in Shattrath and Scryer one in Shadowmoon Valley or otherwise). Also, the quest is available only with Neutral or above reputation with corresponding faction.
Candy bucket locations