I went to EMFCamp the last time it happened (2012) and enjoyed it, so am intending to go this year. It's at the end of August near Milton Keynes.
Description from the website:
"Electromagnetic Field (EMF) is a non-profit UK camping festival for those with an inquisitive mind or an interest in making things: hackers, geeks, scientists, engineers, artists, and crafters."
I've already started to think of what I can make and take along to it.