Pen/Highlighters tool in Power Point Presentation

After reading the how to geek, I realized that one can easily use the highlighter tools in the power point slide- show to highlight stuffs. One can use the pen tool to mark things during the slide show or use the highligher. This is pretty handy. One does not need to use sticks which are generally long or laser pointers as it can show your shaky hand (when nervous) on screen :P
Just go to the bottom-left corner and click on the pen tool.

Or right click on the screen

One can also choose the color of the pen.
Then highlight or mark the slide!

Useful!
Thanks: http://www.howtogeek.com/howto/19924/use-your-mouse-as-a-laser-pointer-in-powerpoint-2010/