If you move around a lot, you may notice that you can't play the same DVDs from country to country. The world is separated into different regions, and not all movies will play in all places. There are ways around this security measure, however, if you follow this tutorial.
This video is a quick, no frills guide to updating your MacBook DVD player for region-free use.
You Will Need:
Warning: Note that these changes are not covered under warranty, so use the software at your own risk. Also, if your DVD player is not listed on the firmware page, it may not be hackable.