Diwali + Kali Puja
Diwali, being about the triumph of good over evil and the festival of light, makes the people light lots of candles, decorate their houses with lights and burst crackers. It has some differences across India, but in Bengal, people believe that on the second day of Diwali, goddess Kali killed a demon, thus giving rise to the Kali Puja. And it’s because these two events are happening at the same time, the celebratory effect is multiplied.
The city turns into something like a WW3 simulation with loud explosions of petards, colorful rockets in the sky and marching music played by (not always) experienced drummers in the street. Children come outside to play with fireworks (with and without adult supervision) and to throw crackers at other people, just to scare them and have a laugh. Also the music in this festival has much more rhythm to it, than the one they played during Durga Puja, so even I joined the marching parades from time to time (don’t even ask for pictures of this).
The rituals during Kali Puja are a lot about offering food and flowers to the goddess Kali. The priests give offerings to Kali (supposedly she eats the food overnight) while chanting mantras for long hours into the night and the drummers join in from time to time to perform.