Tired of the person who stands up and delivers a repeat of their presentation (they are as bored as you)? Tired to the point of not being able to concentrate for more than the first few minutes of a presentation? Tired of making it through to someone's lecture to discover afterwards you have no idea what you learnt?
John Medina is a scientist who researches ways to avoid problems like these. He also has some very practical advice. I like his Brain Rules website, with videos (nice to see him practising what he preaches), tips and links to a new book. Each of his 12 rules are available with illustrations and videos.
Advice for a 50 minute presentation? Break it down into 10 minute segments. At the end of every segment add a hook / statement that will generate an emotional response in the listener. I'll be trying that for my next presentation.