Annakuta-mahotsava is a festival commemorating the day when the Lord lifted Govardhana hill to assure protection to His devotees. The Lord assumed a gigantic form and accepted all the offerings made by His devotees. This is recounted in Chapters 24, 25, 26 and 27 of the Tenth Canto of Srimad-Bhagavatam.

Sri Giriraja-sila, who normally resides in the Radha Madhava altar, comes out and the pujaris perform an abhisheka ceremony for Him at noon. An annakuta (“a small hill of rice”) is made and decorated with vegetable carvings, sweets, cakes, sabjis and colored rice varieties. A miniature form of Govardhana and surrounding lakes are constructed by some devotee ladies and children. This is displayed near the Nrisimhadeva shrine (to Lord Nrsimhadeva’s left) and devotees partake while doing parikrama. A feast to the resident devotees is served inside the temple hall.

Source: Mayapur.com