The Sacred Eleventh
Ekādaśī (Sanskrit: ekā = one + daśī = tenth; the eleventh day) falls twice monthly on the eleventh tithi (lunar day) of the waxing and waning fortnights. It is the most universally observed fast day in the Vaiṣṇava tradition and holds particular significance in the Śrī Vaiṣṇava calendar.
The Fast
On Ekādaśī, observant Śrī Vaiṣṇavas abstain from all grains and beans (dhānya), observe the day in prayer, recitation of the Divya Prabandham, and if possible attend temple worship through the night (rātri jāgaram). The fast is broken on the morning of Dvādaśī (the twelfth day) with pāraṇai.
Vaikuṇṭha Ekādaśī
The most celebrated Ekādaśī is Vaikuṇṭha Ekādaśī (Mokṣadā Ekādaśī) in the Tamil month of Mārgaḷi — when the paramapada-vāsal (the door to Vaikuṇṭha/Paramapada) is ceremonially opened at Śrī Raṅgam and other temples. Lakhs of devotees gather to pass through this door as a symbolic enactment of liberation. This Ekādaśī is also the tirunakṣatram of Nammāzhvār.