Original: The most important festivals of Vithoba are held on the eleventh (ekadashi) day of Hindu lunar months: Shayani Ekadashi in the month of Ashadha, and Prabodhini Ekadashi in the month of Kartik.
Simplified: The two most important festivals associated with Vithoba are Shayani Ekadashi in the Hindu month of Ashadha, and Prabodini Ekadashi in the Hindu month of Kartik.