There are no major festival dedicated to Brahma, is the creator of the universe and one among the Trimurti. There are numerous festivals dedicated to Shiva and Vishnu and to Mother Goddess but there are no festival dedicated to Brahma. The reason is philosophical and is told through the story of Shiva cutting the fifth head of Brahma.
Legend has it that Lord Shiva was disappointed with the world that Brahma created. Shiva saw disease, pain, suffering, death… in the world. He saw human beings madly scampering for momentary pleasure under the influence of Maya.
But Brahma was happy with his creation and he brought forth four heads to look in all direction. Brahma’s pride knew no limits and he popped up a fifth head to have a look at his creation. This pride of Brahma enraged Shiva and he became Bhairava.
Shiva as the ferocious Bhairava attacked Brahma and he cut off the fifth head for creating a world filled with misery, Shiva cursed Brahma that people will not worship him and will not conduct pujas, rituals and festivals in his name.
Brahma is usually depicted as an old man who is still chasing desires. Creations are the result of his desires. He is not blessing the living beings with the knowledge to overcome Maya.