Free, Performant, Easy-to-use subdomains for any project!
If you haven't already, log in to your GitHub account and set up your GitHub Page by following the instructions here. To get a head start you can simply use the generator with one of the provided themes and add some content to your new page.
Now determine your hexx.page subdomain: either choose your username or the name of your repo according to the existing GitHub Pages URL (for http://foo.github.io/bar, either foo.hexx.page or bar.hexx.page would be possible).
Add a file named CNAME to your repo (in the gh-pages branch for project pages) with a single line matching the domain you have chosen (e.g. foo.hexx.page). If you prefer a webinterface form, have a look at the GitHub Pages Help.
Finally, make a pull request in this GitHub repository that adds your subdomain to the list of existing HEXX.PAGE domains. Your new URL should go live within 24 hours (keep an eye on your pull request in case of a naming conflict).