How do you block people off of your Gmail account?

Just above the chat section in the gmail page, you should see "Contacts" Click on it. Browse through "All Contacts" and find your friend... Click his/her name You will see beside "Show in Chat List" that they are blocked. Click on the drop down menu, and select Auto or Always, depending on what you want to happen... Et Voila, they will be added magically back into your chat list.