This is a data:text/html URL that lets you play games. The only website it depends on being unblocked is data url's (ofc) and jsdelivr (usually unblocked because it is a widely used cdn). Note that not all games work since data urls don't support features like cookies, local storage, etc.
Simply go to this URL in your browser:
data:text/html;charset=UTF-8;base64,PGh0bWw+PGhlYWQ+PHRpdGxlPkxvYWRpbmc8L3RpdGxlPjwvaGVhZD48Ym9keT48c2NyaXB0PmZldGNoKCJodHRwczovL2Nkbi5qc2RlbGl2ci5uZXQvZ2gvQnJhZGxleUxpa2VzQ29kaW5nL3RoaW5neS9pbmRleC5odG1sP2NiPTEyMyIpLnRoZW4ocmVzcG9uc2U9PnJlc3BvbnNlLnRleHQoKSkudGhlbihodG1sPT57ZG9jdW1lbnQub3BlbigpO2RvY3VtZW50LndyaXRlKGh0bWwpO2RvY3VtZW50LmNsb3NlKCk7fSkuY2F0Y2goZXJyb3I9Pntjb25zb2xlLmVycm9yKCJGYWlsZWQgdG8gbG9hZCBjb250ZW50OiIsZXJyb3IpO2RvY3VtZW50LmJvZHkudGV4dENvbnRlbnQ9IkVycm9yIGxvYWRpbmcgcGFnZS4iO30pOzwvc2NyaXB0PjwvYm9keT48L2h0bWw+