How To Make Category a Homepage?

Hello there. I don't want to install multisite because I have to pay extra for Vaultpress and also because some of my plugins are not compatible.

There is only one feature of Multisite I would like, and that was to make each category a homepage, so I could of created a multisite for Gaming for example, and then that would appear at http://domain.com/gaming but instead of being archive.php it would be a new homepage, as it would be a multisite. Of course I could also have done subdomains, but these days they all work the same in the eyes of a search engine.

So, my question is: How do I make my categories appear as homepages instead of archive.php?

I don't mind each post still appearing as the main site, I just want to customise the categories so they act more like a seperate site homepage.

How would I go about doing this?