Without joining a company (which also works on php-mysql), you can not get real world experience! Until you get a global certification on PHP-MySQL, I think you can’t get proper offer on the same field. For Certifications.
You can also try to set up “Cross Browsing Web Test Lab”!
You can try to this:
Create an online quiz using PHP & MySQL. Which like quiz to be 10 questions, True/False, 1 question per page and 1 image per page. Each page would have a ‘next’ button and then at the end the user would get his/her results. (This is just for an Idea…., you can get your from your own)