You have to buy a domain first to host a website, then you have to either get a static IP or setup Dynamic DNS, establish the web server, create a DMZ for the server, configure DNS, setup FTP, and set user access rights. Then you have to find clients if you want it for commercial use. If it's for commercial you will want redundant hardware, a business class line, and incorporate a business to simplify taxes.
Many games you cannot host anymore (Battlefield comes to mind).