Mod_dtcl is a free/open source implementation of server-parsed Tcl under Apache. It allows you to tightly integrate HTML with Tcl, a widely-used scripting language with many years of development invested in it. There are also many external Tcl modules that you can load into mod_dtcl, to create images, access databases, etc.
mod_epp is an Apache 2.0 module that implements the EPP over TCP protocol as defined in draft-ietf-provreg-epp-tcp-06.txt and the session management parts of draft-ietf-provreg-epp-0(6|7|8).txt. This is not a full implementation of EPP; this module just makes it possible to write an EPP server as a set of CGI scripts.
mod_log_spread is a patch to Apache's mod_log_config, which provides an interface for spread to multicast access logs and per-vhost logs. It utilizes the group communication toolkit Spread for reliable multicast transport. mod_log_spread was developed to solve the problem of collecting consolidated access logs for large web farms. In particular, the solution needed to be scalable to hundreds of machines, utilize a reliable network transport, allow machines to added or dropped on the fly, and impose minimal performance impact on the Web servers.
mod_log_sql (formerly known as mod_log_mysql) is an Apache module that enables access logging to an SQL database. This capability can replace or coexist with Apache's regular text-file logging mechanisms. The currently supported database backend is MySQL, with PostgreSQL and others in development.
The Apache/Perl integration project brings together the full power of the Perl programming language and the Apache HTTP server. With mod_perl it is possible to write Apache modules entirely in Perl. In addition, the persistent interpreter embedded in the server avoids the overhead of starting an external interpreter and the penalty of Perl start-up time.