As the name suggests, "Shivratri" is a festival in the honour of Shivji. Its a popular festival in North India and people observe fast for the day. There are two stories behind this festival - one says that Shivji married Parvatiji on this day, while the other says that this was the day when the samundar manthan took place during which a pot of poison emerged from the ocean and it had to be consumed before the manthan could be resumed. It was then that Shivji stepped forward to rescue the Gods and the demons and consumed the poison - turning blue because of it.
As part of the puja we bathe the shivling with milk, water and sugar. Two particular offerings made to Shivji are the bel leaves and dhatura (a fruit). We prepared kuttu ki pakodi and makhane ki kheer (thanks to Ma!) for the special dinner - no Indian festival is complete without delicacies :). Sometimes we have aloo ki tikki. Some day I'll upload recipes for these.