It's family-friendly, only £10/day, including lunch, and features an outstanding and fascinating array of speakers, as well as live music and a hardware-hacking bag for attendees.
The site's 35 minutes from Leeds and Manchester, and the speakers cover topics from steam-powered technology to future microprocessor design to civil liberties and surveillance. There's an open source hardware camp with presentations ranging from bootloaders to "open storytelling."
Wuthering Bytes – 15th to 17th August 2014
(Thanks, Andrew!)