I personally like to split my emacs into three windows. I have a certain setup that I like, and I wrote a function to quickly execute the command sequence C-x 3, C-x o, C-x 2. This way I can quickly switch back and forth from a one to three window setup by typing: M-x split-windows.

I'm quite terrible with Lisp, so I'm posting here so I can remember what I did. I'd like to someday make improvements so that it remembers which buffer was open in each window, but this will do for now.

;; split windows
(defun split-windows ()
  (interactive)
  (split-window-horizontally)
  (other-window 1)
  (split-window-vertically))