OSCON in Austin. If you'd like to get an "Expo Hall Plus Pass" for free (usually $99), use OSCON17XPO to register. Read more about that pass type here: https://conferences.oreilly.com/oscon/oscon-tx/public/content/exhibitplus.
Please note, this pass doesn't cover keynotes or general sessions... but there's still a lot of cool stuff you can see with it. I'm going for some part of it.