I wrote this as my comment for reiko, but I just thought that some people may enjoy it, so I put it up here.
Star Festival is callede "Tanabata" - have you heard of it? In Japanese old legend, once upon a time, there was a star girl and a star boy in the sky, both hard working young people, but they fell in love, became too eager to date all the time and stopped working. So the god in the sky got angry and made a big river between them so they cannot see each other. That is Milky Way. But they were so sad and the god felt sorry a bit, so he sends a huge swan who spreads his wing over the Milky Way to become a bridge, so they can meet once a year, on July 7. The swan is Cygnus.
So if it rains or cloudy on July 7, the lovers cannot meet. They used lunar calender in the old days, so July 7 was in mid-summer, but in solar calender, it falls during the rainy season, so I guess they have missed lots of dates since Japan adopted the solar calender!
On July 7, people decorate bamboos with colorful origami crafts, and hang cards with their wishes written on it, so the god in the sky hears their wishes, too.
I think it is the most romantic trandition in Japan.