What are you most excited to see in the series that didn't appear in the movies?

I am re reading OOTP and personally the whole San Mungo scenario with Ron and Hermione finally knowing about Neville's parents and the heartbreaking scene of Alice Longbottom giving Neville a Drooble's Best Blowing Gum wrapper. It will surely put Bellatrix into a darker light when the DA meets her at the Ministry of Magic.