The emacs function that seems nifty to me at the moment is open-rectangle. It is bound to the key sequence C-x r o. Unless I set that up specially, it is probably bound the same way in your emacs environment. Below is its documentation, which can be obtained with M-x describe-function open-rectangle.

open-rectangle is an interactive compiled Lisp function in `rect'.
(open-rectangle START END &optional FILL)

Blank out the region-rectangle, shifting text right.

The text previously in the region is not overwritten by the blanks,
but instead winds up to the right of the rectangle.

When called from a program the rectangle's corners are START and END.
With a prefix (or a FILL) argument, fill with blanks even if there is no text
on the right side of the rectangle.

Have fun!