People dance around the center stage, on which drums are set up.
We offer food for the spirits of our ancestors.Yesterday I went to a nearby shrine where a traditional festival was being held. Such a kind of festival is held nationwide around the 15th of August. About three to five days period including the 15th is called "Obon", when people take vacation and it is believed that our ancestors' spirits come back to the world we live in. So the shrines in Japan welcome those spirits with "Obon Festival Dance". And we put offerings like food in front of a shrine or tombstone for the purpose of serving the spirits of our ancestors.
But there are many cases where this kind of festival is more like secular than religious. In these cases, people invite people in a city and stalls to a place around the station and let them participate in Obon Festival Dance.
I think you have seen the episodes "Endless Eight" of The Melancholy of Haruhi Suzumiya where the members of the SOS brigade are enjoying the Obon festival on a night and Yuki buys a mask from a stall.
