According to Osho, true celebration is the flowering that happens when we stop choosing between body and soul, outer and inner. Man is a gestalt duality; East denied the world, West denied the soul—both are half. Celebration means living the totality: using the gifts of the outer while being rooted in the inner, so life is whole, present, and joyous.
To really celebrate, enjoy the world while staying aware inside—love both your body and your soul.