The first “extra thing to do” appears in The Standing Stones. You will pass through a curtain into a large open area after being told that nasty things are still coming out of the sun. At the back of the area is a gopher sat under a chair. Speak to him and he will tell you to use gophers to shoot a basket at each of the three basketball nets around the edge of the area. Once you have done this, he will open the blue present that is sat next to him.