The Weaving Maiden was the youngest of seven daughters of the Queen of Heaven.  She wove the most beautiful silks.  One day, her sisters persuaded her to go down to earth for some fun and games.  While there, the girls decided to go skinny-dipping.  As they disrobed, the cowherd happened to be watching from the bushes, and he fell head over heels in love with the beautiful Weaving Maiden.  So, as the girls were bathing, he stole her clothes.  When they came out of the water, the sisters put their robes on and flew back up to heaven, but the Weaving Maiden had to chase after the Cowherd for her clothes.  She ended up falling for him, and decided to stay on earth to be with him.
After a while, the Queen realized her daughter was missing.  She hunted high and low, and found her dallying with the Cowherd, and dragged her back up to heaven to resume her weaving duties.  When the Cowherd tried to follow, the Queen waved her golden comb across the skies, forming the Milky Way, which separated the two lovers.
Everyday, the Weaving Maiden pined and cried for her Cowherd, until her father took pity on them.  He decreed that, henceforth, on the seventh day of the seventh moon, they would be allowed to meet.  So every year, on that day, the magpies would fly down from heaven, and form a bridge across the Milky Way, and the lovers would meet over the backs of the magpies.  And those of us looking up on that day will see this bridge of magpies as a rainbow.