It was pretty simple, you go in and have a nice calm chat for a little while and they basically ask you a few questions about why you want to go there, and they try and find out how committed to it you'll be. Then you have your actual audition, and I choose to play something gay and simple that I knew inside out to a backing track... Stockholm syndrome. But yeah they're really nice about it, and for the improv they just throw a few chords at you to use and improv around. No pressure at all about it, but it's a lot more nerve racking before hand though. Have a few drinks before hand.