One Piece: Stampede

The world's greatest exposition of the pirates, by the pirates, for the pirates - the Pirates Festival. Luffy and the rest of the Straw Hat Crew receive an invitation from its host Buena Festa who is known as the Master of Festivities. They arrive to find a venue packed with glamorous pavilions and many pirates including the ones from the Worst Generation. The place is electric.

(Source: Fuji TV via AniDB)