I think it would be smart to encourage people to visit chat rooms during Beta. It will create think-tank environment where topics for questions could be discussed. Is something like that feasible/good idea to do?
It took a long time for me to visit Chat. Chat seemed to me, when I was a relatively new and low-rep user, as an in-group of the awesomely accomplished elect. They still seem awesomely accomplished -- or at least awesomely energetic -- but I no longer feel shy about posting in Chat.
I think the suggestion to more explicitly urge users to visit Chat is a good one. Silly comments will be ignored and good comments may spark good questions.
We don't really need a banner - we've already got a small box on the right-hand side that says
The Great Outdoors and it is clearly a link for a chatroom:
So if people want to visit chat, they can look for it, I think it is obvious enough Also, there is a
chat button on the top navigation bar (whenever there is not a new blog post alert), another way to get to chat.