Emacs exercises to become more comfortable and familiar with the editor itself as well as Lisp?

There used to be lesson in .el format (emacs lisp) at http://www.gnuvola.org/software/elisp-tutorial/.

You can find a copy of the tutorial here now.

I learned a lot from them. You read them in emacs in lisp interactive mode, and practice within the text.

The book, "Writing GNU Emacs Extensions", comes pretty close to what you're asking for.

But, if you don't want a book, there are three similar questions already in stackoverflow: What's the best way to learn lisp, How to quickly get started at using and learning emacs, and Tips for learning elisp.

I don't know a "walk through" series that exists, but have found that the best way is to start thinking about little things you wish it did, and then trying to make it work (asking here helps). Even if Emacs already provides such functionality, you might find it more interesting to solve problems you want solved, rather than a bunch of throw-away lessons that hold little interest to you.

The The Little Schemer is a book of Lisp exercises. You need to be aware that some of them are impossible in Emacs Lisp, as it doesn't support closures.

It is also focused on teaching recursion to non-programmers, meaning that you won't cover the full range of Lisp statements (most exercises just use (cond ...) recursively.)

I really enjoyed it though.