Electromagnetic Field, the biggest maker/hacker event in the UK, and it was awesome.
You get something like 1400 like minded people in an environment akin to a music festival.
There's simply so much going on it's hard to get a balance between attending talks, socialising, playing with the various installations people bring and actually doing some making or coding.
To try and inspire everybody to have a go at the latter they produced this fantastic event badge. They've really pushed the boat out with this, it's got a colour screen, Wifi, accelerometer, compass, piezo sounder, LiPo battery/charger etc. etc. It runs MicroPython and you can connect to it as USB mass storage so it's possible to write code directly for it from almost anything with a USB port and a text editor.
Most impressive of all, while it doesn't exactly have an OS they have produced an ecosystem for it. The 'home' app is a menu system for accessing other apps and there's an 'app library' on a server you can install things from and a mechanism for updating them once on. Also people could upload code to the app library while at the event and by the end there were 69 apps in there.
Obviously some of these apps were broken/trivial/stupid but by the end I saw people wandering around with all manner of homebrew stuff on the screens of their badges. Best of all was an old school Elite style line drawing of a 3D cube rotating.
Sadly it's only a biennial event so I can't look forward to it in 2017 but I'm definitely going to make plans to go in 2018.