The one plot flaw is that Atticus or Aunt Alexandra would have gone to the pageant. It was a big event in Maycomb, and their daughter / niece was in it. Also, Alexandra was in the same social circle as Mrs Merriweather the organizer of the pageant, and Alexandra wouldn't snub Merriweather by not attending.
Incidentally, I've noticed what I think is an error in the Merriweather section on Wikipedia, let me know what you think of my edit.
The book was lent to me ages ago by Clive at work. For some reason it sat unread on a table in my dining room, on top of Matt's collection of Clint Eastwood western DVDs. I've received increasingly strong hints from Clive about returning the book, so I read it on Friday / Saturday. Just gotta remember to put it in my bag, and then hand it to him.
Back to the book. At the end they were wrong to cover up what actually happened with Ewell. There should have been a proper investigation. What do you think?
Btw, I'm not very good at saying how good a book is. Needless to say, this is a good book.