This is one of the major holidays for Hindus associated with Lakshmi, the goddess of prosperity, and it symbolizes the spiritual "victory of light over darkness, good over evil, and knowledge over ignorance." A loose retelling of a story associated with Diwali can be found here.
We have a lighting ceremony taking place at Grimmauld Place tonight around 6 PM, if anyone wants to join us. There will be food and fireworks right after. Then, as usual, there is karaoke at Galahd tonight from 8 PM to 10 PM. I will only be doing Bollywood songs in honor of Diwali, so come if you want to not understand a word I'm saying! You're all free to sing whatever you want. :)