What are the key points from chapters 22-27 in Harper Lee's To Kill a Mockingbird?

Chapter 22 of To Kill a Mockingbird picks up after Tom has been convicted of rape. The key event in this chapter is that they discover that Bob Ewell threatened Atticus and spat in his face. Another important event occurs in chapter 24 when we discover that Tom has been killed in an attempt to escape from prison. The appeal Atticus hopes to bring before a judge will never happen, and justice will never be served for Tom. Atticus has the unenviable task of going to tell Tom's mother in chapter 25.
In chapter 27 we learn that Bob Ewell is still up to no good, and that he has not yet given up on avenging what he perceives as Atticus's attempt to humiliate his family in court. It is also announced that Scout will participate in a school pageant, dressed as a ham. This leads to a very important event in the novel, which occurs in chapter 28—Bob Ewell's fateful attack on the children on the way back from the pageant.