Haxball Unblocked Official
If you want to guarantee access for you and your friends, you can host the game locally using the open-source nature of the Haxball client (there are GitHub repositories for the headless client). This requires technical know-how, but it allows you to run the game on a private server with a custom URL that no firewall recognizes.
Disclaimer: This article is for informational purposes only. Always adhere to your school or employer’s acceptable use policy regarding internet access. haxball unblocked