Pollyanna

Yes, there is a well-known Disney film adaptation from 1960 starring Hayley Mills. The movie captures the spirit of the book, though it does take some liberties with the plot and character developments.

Yes, Eleanor H. Porter wrote a direct sequel titled 'Pollyanna Grows Up.' Additionally, other authors continued the series with numerous further books, expanding on Pollyanna's life and adventures.

The 'Glad Game' is a central concept in the book where Pollyanna finds something to be glad about in every situation, no matter how dire. It's a coping mechanism taught to her by her father, which she then shares with others.