RepoForge (formerly RPMforge) is a repository of software packages for Red Hat Enterprise Linux and derivatives such as CentOS and Scientific Linux. It provides many packages in the rpm package format to these distributions.
RepoForge also has many RPM packages available for old distributions like Red Hat 8, after they are no longer supported by their vendors. Their repository can be accessed via package management products like apt-get and yum; up2date does not work any more due to expired SSL keys.
References
RepoForge Wikipedia(Text) CC BY-SA