unfortunately, festivities surrounding Chinese Valentine's day have
fallen off in recent years. Maybe it isn't that popular lor!
in the past, as told by my ah-ma they would put up colorful
"shrines" made of paper, fresh fruit, and flowers as a tribute to
Niu Lang and Zhi Nu.
According to the first version (my favorite), the seven daughters
of the Goddess of Heaven caught the eye of a Cowherd during one of
their visits to earth. The daughters were bathing in a river and
the Cowherd, Niu Lang, decided to have a bit of fun by running off
with their clothing. It fell upon the prettiest daughter (who
happened to be the seventh born), to ask him to return their
clothes 
of course, since Niu Lang had seen the daughter, Zhi Nu, naked :p,
they had to be married. The couple lived happily for several years,
until either the cowherd died or the Goddess of Heaven simply
became fed up with her daughter's absence and ordered her return to
heaven. In any event, the mother finally took pity on the couple
and allowed them to be reunited once a year. Legend has it that on
the seventh night of the seventh moon, magpies form a bridge with
their wings for Zhi Nu to cross to meet her husband.
in the second story, Niu Lang and Zhi Nu were fairies living on
opposite sides of the Milky Way.
Feeling sorry for the two lonely sprites, the Jade Emperor of
Heaven actively tried to bring them together. Unfortunately, he
succeeded too well - Niu Lang and Zhi Nu became so enraptured with
each other that they neglected their work. Annoyed, the Jade
Emperor decreed that from that point on, the couple could only meet
once a year - on the seventh night of the seventh moon.
so which version do all of like huh? of course the 1st, rite?
therefore, tonite nothing to do, please stare @ the sky.......look
out 4 the Milky way from east(zhi nu) to west(niu liang) 
if u r 'heng' enough, u can even feel the 'qi xi
yu'.......hahaha it's the 'xi qiao' sia :p