CKEditor HTML Insert is a plugin for comfort inserting HTML code onto page you edit. It highlights HTML syntax, and lets you ability to insert new code and edit selected existing code. Also you are able to format the code with this plugin.
You click "HTML" button and dialog with advanced HTML editor shows. All HTML you write there is inserted to current cursor position in CKEditor.
Plugin does not any additional quoting, escaping and other, so it is a perfect tool for pasting objects for embedding, such are YouTube videos for example.