I recently stumbled onto the filming of a TV pilot, and saw some behind-the-scenes stuff that perhaps you might be interested in.
I found out that the opening credits, where the audience are screaming the host into existence, are actually filmed in the middle of the show. This is because the audience is not actually warmed up at the beginning of the show but will be by the half-way mark (at least you'd hope so).
On TV, when you see the host rush out in front of the audience at the top of show, it's actually the second time that the host has rushed out. We were told this, at the half-time interval by some bearded guy, who was not the MC but popped out onto the stage, who proceeded to explain the filming of the opening sequence to us.
We were told to scream like a bunch of rabid monkies, and, of course, being a bunch of celebrity-starved attention tools, we cheered on the host back on stage to welcome us once again.