Stainsby Festival, the longest running festival of its kind, is next weekend (19th - 21st July). This small, family-friendly festival has a great line-up as usual, as well as a real-ale bar, and cosy camping field. Guaranteed 100% not-for-profit, the festival is entirely run by volunteers. There are still a few tickets left I believe.

http://stainsbyfestival.org.uk/