Converse, shorts/stretchy trousers, vest/t shirt and jumper, depending on temperatures. Soooo basically what I'd be wearing if I wasn't at Glasto. I can't be arsed dressing up at the best of times, let alone when I'm living in a tent and caning it for 5 days. What I'm wearing, beyond keeping warm and dry enough, is the least of my priorities.
You'd have to be a maniac to wear a jumpsuit.