The way how Addy Osmani implements singleton pattern is rather disputable. I would implement singleton as a regular object that returns itself immediately if initialized for the second time.
His prototype pattern also doesn't look like the right way of doing things. Is there actually anyone that uses plain object descriptors? I would just create helper method that wraps Object.create() and takes prototype object as first argument and instance object as second argument. There is no need to use constructors in this pattern (either directly or inside helpers) unless you are targetting legacy browsers.
I also dislike the fact that public/local scope is emulated by misusing the return statement - this is ugly, confusing and it doesn't play nicely with other patterns such as prototype. If you need some notion of public/private scope then just use underscore notation.