Vaikunta Chaturdasi is observed on the 14th day of the Shukla Paksha or waxing phase of moon in Kartik Month. Vaikunta Chaturdasi 2013 date is November 16. The popular belief is that on Vaikunta Chaturdasi day Srihari Vishnu received the Sudarshana Chakra from Shiva.
Special pujas and rituals are held on the day by certain communities to Shiva and Vishnu.
You can read the story of Vaikunta Chaturdasi here in this earlier article.