Not being much of a fruit lover i do not attend events such as this - BUT I do read that -
Rayong is renowned for its abundance of tropical fruits and the best buys include rambutan, durian, mangosteen, longgong and zalacca. During the fruit season in the middle of May, the annual fair is held to provide a market for the locals from surrounding orchards to sell their fruits and other local products. The venue has been alternating between Rayong municipal town and Amphoe Klang. The fair has stalls selling local fruits and products.
Colourful floats are decorated with fruits and flowers. Parades, musical entertainment, and dance processions wind through the streets of the provincial town. There are beauty pageants, fruit contests, local products and agricultural crop displays and exhibitions. Some of the major highlights are cultural performances and folk entertainment.
Text is from Thailand.com.