I was going to do a lot more than I've been able to manage over this weekend, having been totally wiped out by a bad cold for a few days.
So I didn't get to the talk about the future of books at the Globe, and I only got to the Quantum Revolution because I'd spent £15 on the ticket and didn't want to waste it.
The foyer of the tent at the Castle this year was quite small - just the Festival Bookshop and gift shop, and a stall selling coffees.
Paul Davies, of the University of Arizona, and Vlatko Vedral from Oxford University, are both physicists, and both have books available.
It's 100 years since quantum theory began, with Heisenberg's Uncertainty Principle, and we're at an exciting time for the future of quantum science. To set up what they were talking about, they explained the many worlds/variable state theory, in which atoms can be seen to be in several different places at the same time, or they can teleport. There are disagreements about whether this means full-on parallel universes (like Mirror, Mirror in Star Trek) or whether it is one universe in several different quantum states at the same time. They're also hoping that recent developments mean that they will be able to work on the problem of how quantum science and General Relativity fit together. At the moment, quantum works for very, very small things, and General Relativity works for big things, but nobody's quite sure how they fit together, or even if it's possible for them to fit together.
There's a race between the world powers to develop a working quantum computer - and fears of a quantum apocalypse, in which the quantum computers could break any current method of cryptography - so bank details, spying, and anything that had been encrypted could be made public.
Hopefully, before that happens, there's potential for a medical revolution, where molecules can be individually tailored to repair cells or block receptors so diseases can't spread. They even talked about the potential for a helmet like something out of a 1960s superhero comic - processes inside the brain cause magnetic fields which can be detected outside the brain, so a helmet that could pick up those fields could literally read your mind! They were thinking more along the lines of people being able to control robots, or prosthetic limbs, though.
There was a digression about geckos - their feet have hairs so fine they extend into the quantum realm, and that's how they can walk across ceilings!
In the questions at the end, they were asked what science fiction they read, and Paul Davies mentioned The Black Cloud by Fred Hoyle - partly because Fred Hoyle gave him his first job! (Watching him on stage, I got the feeling that he would have enjoyed the company of Brian Aldiss). Vlatko Vedral said it was very difficult to go to the movies as a physicist - what was portrayed in Interstellar, for example, doesn't work like that!
Another question was on ethics - is there an ethics department working alongside the physicists to maybe say "Well, you could do this - but should you?"
They obviously do take ethical considerations into account - but knowledge of quantum science is worldwide, and maybe everyone wouldn't be quite so careful.
By the time I got out of the marquee, the Christmas Lights had been turned on, but the square was still full of people - and traction engines, and a fire engine.