Tanabata, the festival that celebrates the star-crossed lovers Orihime and Hikoboshi, takes place across Japan in early July (and some in August). You'll find one of Tokyo's longest-running iterations of this event in the western town of Fussa.
While other such festivals tend to be fairly low-key affairs, this one (now in its 76th year) is packed with events, including a Princess Orihime contest and a folk dance parade with mikoshi floats. The latter is making a comeback on Friday from 6pm, starting at Fussa Station’s west exit and ending in front of Fussa City Hall. There are also shows and cheerleading performances on Sunday. Plus, of course, plenty of food stalls around Fussa Station throughout the duration of the festival.