Now that we can easily make a region based on "syntactic components" using the `expand-region` command, wrapping a logical block of text with a beginning and ending string really makes sense. This "version" is more Emacs-y in that it `lets` all the variables, and then `setq` them to their proper values. While I'm not pedantic, I don't like such …

surround-v2.el

(defun surround (start end txt)
  "Wraps the specified region (or the current 'symbol / word'
with some textual markers that this function requests from the
user. Opening-type text, like parens and angle-brackets will
insert the matching closing symbol.

This function also supports some org-mode wrappers:

  - `#s` wraps the region in a source code block
  - `#e` wraps it in an example block
  - `#q` wraps it in an quote block"
  (interactive "r\nsEnter text to surround: " start end txt)

  ;; If the region is not active, we use the 'thing-at-point' function
  ;; to get a "symbol" (often a variable or a single word in text),
  ;; and use that as our region.

  (if (not (region-active-p))
      (let ((new-region (bounds-of-thing-at-point 'symbol)))
        (setq start (car new-region))
        (setq end (cdr new-region))))

  (let (s-table s-pair front-text back-text)

    ;; We create a table of "odd balls" where the front and the end are
    ;; not the same string.
    (setq s-table '(("#e" ("#+BEGIN_EXAMPLE\n" "\n#+END_EXAMPLE") )
                    ("#s" ("#+BEGIN_SRC \n"    "\n#+END_SRC") )
                    ("#q" ("#+BEGIN_QUOTE\n"   "\n#+END_QUOTE"))
                    ("<"  ("<" ">"))
                    ("("  ("(" ")"))
                    ("{"  ("{" "}"))
                    ("["  ("[" "]"))))
                    ;; Why yes, we'll add more

    (setq s-pair (assoc txt s-table))
    (if s-pair
        (progn (setq front-text (car s-pair))
               (setq back-text (cadr s-pair)))

      ;; If txt doesn't match a table entry, then the pair will just be
      ;; the text for both the front and the back...
      (setq front-text txt)
      (setq back-text  txt))

    (save-excursion
      (narrow-to-region start end)
      (goto-char (point-min))
      (insert (car s-pair))
      (goto-char (point-max))
      (insert (cadr s-pair))
      (widen))))

(global-set-key (kbd "C-+") 'surround)