Earlier quoted context omitted.
I got baited into going to one of those once. I was promised the prospect of spending a dozen hours with friends building something cool, but halfway through I realized we were just doing free labor for one of Latin America's biggest banks and just left. I'm still longing for events where my friends and I can gather to build something cool, and game jams are the closest I ever got to that.
+1 had a fun Node Knockout experience many years ago making a game with 3 friends. We had a game artist / sound designer, and two engineers with chops on the front-end and back-end.
In which the Judges have to actually try out the submission instead of listening to people go through a slide deck on a video.