Sankrant the first festival of the Calendar year(Jan-Dec). It is generally celebrated on 14th Jan/15th Jan. It is called a harvest festival and celebrated differently in various geographies of India.
More detail can be read @http://en.wikipedia.org/wiki/Makar_Sankranti
The way we celebrate it at home is make Til-gul wadi, wear black and make bhogi chi bhaji. Bhogi chi bhaji(vegetable) is made using most of the vegetables available in market in this season . It is had with bajra roti.
In Maharashtra people celebrate “pehli makar-sankrant” for the newly weds and toddlers(1-5) years. They are supposed to wear black and wear specially made halvyache dagine.
For toddlers, we also have “bor-nhan(bor=jujube and nhan=bath). The kid dressed up in Krishna attire and then bathed with bor,chocolates,biscuits, coins and whatever the parents wish too..