In the Hindu tradition, Thursday is known as Guruvaar or Guru Day. The Guru — dispeller of (spiritual) darkness — is honored by fasting, silence or other observances dear to the nature of the disciple.
I lived in India for a few years and found myself enchanted by the way Indians live their spiritual life in oftentimes noisy, colorful and celebratory ways. There is ALWAYS some sort of festival or religious observance happening privately, publicly and with deep devotion.