Jack is scheduled to go on stage in 45 minutes, at 10:00 PM Poland time, so 4:00 PM ET/1:00 PM PT. They're going to be streaming his performance live on the Open'er Festival website, http://opener.pl/en. I don't think they'll have a broadcast of it afterwards. I'm don't think people in the US can watch the stream though.
EDIT: Using Tunnelbear works, though.
Edited by matthewvh, 04 July 2014 - 02:22 PM.