The glories of Mohini Ekadasi which occurs during the waxing moon in the month of Vaisakha are told in the Surya Purana.
Once Maharaja Yudhisthira asked Lord Krsna, "O Janardana! Pray tell me, what is the name of the Ekadasi that occurs during the waxing Moon in the month of Vaisakha (April/May.) Please describe unto me the most meritorious benefit one may receive by such observance.

Sri Krsna replied: "O most merciful King, son of Dharma personified! Please hear Me attentively as I describe unto you the story that the great sage Vaisistha once told to Lord Ramacandra.

Sri Rukhmini Dwadasi, is observed as the birthday (the day Rukmini Devi appeared on earth) of Rukmini, the consort of Lord Krishna.

The love story of Rukmini and Lord Krishna and their elopement is one of the most famous stories associated with Lord Krishna. Rukmini Dwadashi is observed on the twelfth day of the Shukla Paksha (waxing phase of moon) of Vaisakh month (April – May). It is believed that those who offer worship prayers and pujas with flowers will have their wishes fulfilled.

Prayers dedicated to Rukhmini Devi are held on the day at Lord Krishna Temples. Special pujas are held at the Dwarkadish Temple in Mathura on the day.

Jayananda Prabhu was a dedicated disciple of Srila Prabhupada’s who helped Srila Prabhupada introduce the Rathayatra festival in the United States.

The appearance anniversary of Lord Narasimhadeva, Lord Krishna’s incarnation as half-man, half-lion.

tava kara-kamala-vare nakham adbhuta-srngam
dalita-hiranyakasipu-tanu-bhrngam
keshava dhrta-narahari-rupa jaya jagadisa hare

"O Keshava! O Lord of the universe! O Lord Hari, who have assumed the form of half-man, half-lion! All glories to You! Just as one can easily crush a wasp between one's fingernails, so in the same way the body of the wasp like demon Hiranyakashipu has been ripped apart by the wonderful pointed nails on Your beautiful lotus hands."