The Chat is telling me I need to login to chat, and when I go to login from there it tells me the meta data is old and to login to any stack exchange site to update it. But I can't login because I'm already logged in and cannot find the logout button....
They removed it recently from the main banner. It's now on your main site profile page. There's 3 links: edit | add openid | log out.
meta.SO question - Logout link now missing
It now appears at the top of every page - move your mouse over the little down arrow to the left of your user name, and you'll see logout in there along with some other useful links.