I am looking for a reddit clone script for my existing site

I currently have a website that has a wordpress home page with a mybb forum inside the site. I am wanting to change the home page to a reddit style site where users can post content with and without links and it be a cleaner, stripped down version of a forum that would allow for upvoting and things of that nature. I know Reddit is open source and you can even use Reddit to build this page. What I need to is to be able to create sub-reddits within my site for categories. I need basically what Reddit uses.