Watching bookaholic punters tramping down windswept country lanes in hiking boots, anoraks and rucksacks instantly alerts you to the singular quality of the Hay Festival, though it's surprising that nobody has grasped the glaring opportunity to set up a tent selling Alfred Wainwright's fell-walking guides and Kendal Mint Cake. But where else can you find such a high density of starry names and media taste-makers in a soggy field on the Welsh border?