Namaste!Teej is the festival of Hindu women honouring their husbands. The first day is called darkhana and at this day women enjoy a real feast: all kinds of curry - mutton, chicken, fish and vegetable, with chutneys, eggs, fruits and sweets. The women often gather in one room and seat themselves on the floor around a spread of dishes. They eat, chat, joke and dance until midnight when the Teej fast starts. Not the finest crumb of food or the smallest drop of water should be taken for the following twenty four hours. This strict fast is performed on behalf of one's husband to ensure his good health and long life.
According to legends goddess Parvati fasted and prayed fervently for god Shiva to become his wife. Impressed by her devotion Shiva blessed her to be his wife. Parvati then sent emissary to spread the message of the religious fasting among mortal women promising prosperity and longevity to their husbands.
An interesting opinion about Teej festival here