Full screen applications and multiple monitors

I have a question:

If you had more than one monitor (2, let’s say) how would your computer handle a full screen application like a game? Would one screen go blank, continue to have whatever was on it before, show part of a game menu, or could you choose what it displays? Certainly, it could be different for certain applications, but in general, what happens?

I’m talking about Windows, incase you weren’t sure :wink: