Help! How to add a random posts menu option?

Hi

I’ve seen in some newspapers the menu option (from the main menu in the higher part of the page) the random content option, which searches from all the content on the website and randomly chooses a piece of content. I find it great to keep the visitor entertained and to promote pieces of content that perhaps havent had the necessary exposure

the problem is the random posts plugins Ive found are more like a related posts thing where it shows at the end of the posts, not in the main menu, and it usually picks content only from the blog part of the site, instead from the entire site.

how can I turn this into a real menu option that can pick any content from my site?

thanks in advance