Big

A 13-year-old boy named Josh wants, more than anything else, to be "big". And when he makes a wish on a carnival wishing booth his dreams come true: he transposes into the body of a 35 year old man -- though his mind and spirit remain that of a child. Since he can't really go to school looking like an adult, and his mother doesn't know him in his new guise, he heads to New York with his pal Billy, where they proceed to goof off, play around, and act basically like the kids they are. But when Billy leaves, Josh is subjected to the encroaching needs and responsibilities of adulthood, and he quickly discovers both the pleasures and the problems of being grown-up.