Summer activities suggestions in Tokyo?

Hey! I'm going to visit Japan with my wife at the end of July to early August (7 days total) to celebrate our anniversary.

This is our second time visiting Japan, we plan to visit two cities, Tokyo and Kyoto. And we originally planned to stay at a resort at Kawaguchiko, near Mount Fuji for the anniversary day, since we missed it the last time due to heavy rain.

But, after reading online that Mt. Fuji has low visibility in July, we are looking for alternatives, any fun experience in July we can do in/near Tokyo in the summer? Thanks!