The Kapil Muni Fair is the largest fair of Bikaner district held on Kartik Poornima at Kolayat-originally Kapilayatan-named after the sage Kapil who is believed to have done tapasya (meditation) here for the redemption of mankind. Kolayat is situated in an arid area. There is a lake with 52 Ghats shaded by banyan trees around the lake. A temple dedicated to Kapil Muni is situated on the Kapil Muni ghat and it has a marble statue of the saint.

A large number of people come to Kolayat to redeem themselves by taking holy dips in the Kolayat lake throughout the year, but it is considered very auspicious to take a dip on Kartik Poornima. The lakeside is dotted with temples. Ghats named after these temples allow privacy to the pilgrims, with some ghats meant only for women. Visiting Kolayat has been considered to be a tirtha or pilgrimage of great importance and it is believed that one day's stay at Kolayat benefits as much as 10 years spent at any other sacred place. The legendary Maharishi Kapil and the Kapilayatan lake find mention in the Puranas and Kapil Muni is believed to have descended from Lord Brahma.

A cattle fair is held in conjunction with the Kapil Muni Fair. Buffaloes, camels, horses and cattle are sold. Certificates and prizes are given away to the best breeders at the fair.Kolayat is situated 50 kms. to the south-west of the city of Bikaner. There is a direct railway route from Bikaner to Kolayat. Regular buses ply from Bikaner to Kolayat.