Kalyana Vratam is one of the eight auspicious vratas. When the Sun is shining in the Pisces sign(mIna rAsi) that is in the month of paN^guni (mid of March to mid of April) on the uththara naxaththiram on the Moons growing face (shukla paxam), this vratam is observed.
This is the day Shakthi married Lord Shiva after a great austerity in the Himaalayas, as the daughter of Himavaan. It is also observed as the auspicious day when Lord Muruga married devaseenaa.
This vratam is explained in the skandha purANam.
In the morning after getting up, the observer of the vratam should meditate on the charming Lord shiva in the wedding posture with umA.
After taking bath and through with other required deeds, should worship the Lord. The golden idol of the God and Goddess ( who can afford to) should be anointed devotionally with holy substances.
Then decorating them should make the wedding ceremony of the Goddess with the God. Making the nice and sweet offerings to the divine Parents, should salute them. Inviting the spiritual people who think of good to all the creatures, who have learnt the vEdas and who are devotees of Lord shiva, along with their wives, should host them a feast.
Later should go to the shiva temple, worship, circumambulate three times and prostrate in front of the Lord.
In the night should dine along with the kind hearted devotees of Lord shiva and eat the sweet dishes like fruits and pAyasam. Should sleep on the dharbai grass. The next morning after regular deeds, should donate the golden idol of God and Goddess to disciplined love hearted people who are the devotees of Lord shiva. Should eat only once that day.
Observing this vratam will get one the great boon of shri Lord sha.nkara's delight.
It would bring much joy and comfort in life, lead to the abode of Lord shiva and give the liberation.
mahA vishNu got wedded to laxmi sincerely observing this vratam. brahma wedded saraswati, indra wedded indrANi, moon wedded the 27 stars, sage agastiya wedded lobhamudra observing this vratam.
The two daughters of vishhNu namely amR^itavalli, saundaryavalli were married to the six faced Lord as devasEna and vaLLI. The daughter of vedAN^ga R^ishhi called sukesi got married to nandi devar.
The two daughters of sage satyapUrNar pUrNa, pushhkaLai were wedded to mahA sAsthA. kAma got rathi, sIta got rAma, jAmbhavati got kR^ishhNa, sage saupari got many princess' and so many more benefitted all in the glory of this vratam.
The man who observes this vratam will get the girl he likes and the woman gets beautiful man as her husband.
The couple who observe this will get good offspring. Anybody who observes with devotion will get His grace.
This auspicious vrata of wedding of shrI pArvatI paramEshvara is celebrated as the festival of colors - Holi.(2) Just preceding this festival is kAmadahanam on which day kAma - the divine of desire/lust is burnt off by the Supreme, as the cupid tried to misadventure his lust inducement on the God Itself.
On the request of divines and pArvatI Lord brought him back to life, during this celebration.