Sacha Chua and John Wiegley posted a wonderful video on Emacs lisp development tips. Embedding the following raw HTML using #+BEGIN_HTML/#+END_HTML:
<iframe width="420"
height="315"
src="https://www.youtube.com/embed/QRBcm6jFJ3Q"
frameborder="0"
allowfullscreen>
</iframe>
results in an embedded video when exporting your org file:
<iframe width="420"
height="315"
src="https://www.youtube.com/embed/QRBcm6jFJ3Q"
frameborder="0"
allowfullscreen>
</iframe>