Depending on what area of Japan you live in the date on Tanabata varies.
It is mostly celebrated on July the 7th but can also be held around August the 7th. This is because the
original date was based on the Lunisolar calendar which is differerent to the Gregorian calendar.
Most people still celebrate the star festival on its traditional date which is on July , while others celebrate it a month later.
The story of Tanabata originated more than 2,000 years ago.
There were once two lovers-a princess called Orihime who wove clothes and a prince named Hikoboshi who was a cow hearder.
They only cared about each other and forgot about everything else. The king then disapproved of them being together and placed them on opposite sides of the milky way.
They were then only allowed to meet once a year on the seventh of July. People now celebrate Tanabata as the star festival.
Before the day of the festival people decorate streets and shops with streamers.
Usually people celebrate the star festival by writing wishes on small pieces of paper them putting them of bamboo. The bamboo is then either set afloat on a river or burned.
This festival is celebrated at night when the stars come out.
In some festivals there are parades and floats
through the streets.
There is also a Tanabata song:
Bamboo-grass leaves flowing in the windSwinging by the edge of the eaves
Stars are shiningLike fine gold and silver sand
Bibliography
http://images.google.com.au/images?gbv=2&hl=en&safe=active&ei=ea6USdmlGYfQ6gOA1vn4CA&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=star+festival&spell=1, 13th Feb 2009.
http://en.wikipedia.org/wiki/Tanabata. 13th Feb 09
http://www.japan-guide.com/e/e2283.html 9th Feb 09
http://gojapan.about.com/cs/japanesefestivals/a/tanabata.htm 17th Feb 09