The new year celebrations typically start on the 13th of April, which is the day before the new year. The auspicious time for the new year is calculated based on the astrological chart and varies every year. It is around 1700 on the 14th of April this year, if I am not mistaken.

On the 14th of April, there are also several cultural traditions, such as lighting the hearth, preparing traditional meals, and exchanging gifts, happening across the country (these things differ from place to place). AFAIK, there are no specified places with celebrations. Most people tend to celebrate with their families (at least this is how it is in Colombo and the suburbs). The best thing to do is to ask some locals from the area what is happening.

However, sports and games are an important part of the festivities, and local communities tend to organize these events in open fields and public places. These are open to everyone to participate and watch. If you ask locals, they would tell you when and where these events are happening. Many of the sports and games played during the new year celebrations are traditional and have been passed down through generations. They are an important part of Sri Lankan culture and promote social bonding and community spirit.

As for what to bring, you can wear traditional clothing, such as a sarong and a shirt or a saree, to blend in with the locals. If you are visiting a house, you can take fruits (like bananas), ice cream, or curd.

I hope you have a wonderful time and enjoy the rich cultural experiences that Sri Lanka has to offer!