Random posts on time line based latest activity?

Hiya, I have a PHP based social networking site, and I would like to know if anyone can make a fungtion for my posts which can show bring the post on the top if it gets like or receive comments. Same as facebook, you fresh the page and you see random posts each time you refresh the main timeline on facebook. Right now my site timeline shows only the latest posts on the top of timeline, but I want to show random posts on timeline each time user clicks. If even old post gets a like or comment that post should appear again on top of timeline. It will keep the timeline interesting and users will see random posts on timeline each time they refresh. Someone already made this feature for me by spending less than an hour on my site. I have his tutorial but when I upgraded my site I lost that custom work. Now when I follow that freelancer tutorial I get errors. I think there is something missing or I do not understand in that tutorial . I can provide you his tutorial if you are good in PHP you will understand quickly within 5 minutes. Let me know please if anyone is ready for this task, this is small task if someone completes I would offer more projects definetely. Cheers