A running festival organised by Colworth Striders where runners can run a 5 miler on the Friday, a 8.1 trail race on the Saturday and a half to round the weekend up on Sunday. Or you could just do one or two of the races. There's free camping and always excellent feedback for this weekend.
A pb is unlikely for most people at this race. A challenging mix of terrain that will make you thankful for the sight of the finishing line! But you'll probably back next year - a great event in an lovely part of the world.