One for the Tolkien geeks out there (among whom, naturally, I count myself). Dr Henry Gee – senior editor of biological sciences for Nature magazine, no less – will be talking about his new book, The Science of Middle-earth, in the hallowed surroundings of the Natural History Museum, at 12 noon and 2.30pm this Saturday and Sunday. Gee, whose book was given the thumbs up by Alok Jha in Life, is unable to answer all the questions thrown up by Tolkien's universe (according to Jha, Gee "has no idea how the ring could make wearers invisible, but can explain why it seems to have a mind of its own, thanks to the latest thinking in string theory"), but will no doubt deliver an entertaining lecture. Ever wanted to know how it is that elves can see so far, how orcs reproduce or whether or not balrogs really have wings? Then this is for you. Anonymity guaranteed.