This is a must go to event! Gion matsuri is one of the three largest and most famous festivals in Japan. The streets of kyoto come alive with this festival. You will see many people dressed in traditional clothing such as Yukata.
It was really lucky to catch this traditional Gion festival. I can join the parade, walk with them alongside and celebrate it with local people. Gion festival is the most famous festival in Kyoto, perhaps in Japan. Although the official celebration last for a week, other related activities can continue for a month. I do advice checking the detailed information before coming. They have activities in various locations and dates, such as folk dance, horse riding, taiko drum shows, bonfire lighting and traditional wooden floats seeing, etc. Also, you can try wearing yukata and enjoying some local snacks like taiyaki, takoyaki, or okonomiyaki. If you like oriental art, there are so many things to see and buy as wonderful souvenirs.