I find coming up with material for school presentations difficult, particularly since as soon as I'm comfortable with the talk I've prepared for blah-blah-blah book, it goes out of print. Then I also like to do something other authors aren't doing. And I like to something interesting. And it's all another ordeal for me to whine about here.
Camille at BookMoot recently did a post on a Scott Westerfeld appearance during which he talked about something that I can't recall hearing other authors talk about and that sounded very interesting. And it was related to his new books, which most definitely are not out of print.