mod_proxy_add_forward.c is an Apache module that adds a 'X-Forwarded-For' header to outgoing proxy requests like Squid does. You can then get the client IP back on the proxied host by setting r- >connection->remote_ip from this header. It's very useful for the common lightweight frontend/heavy backend mod_perl setup.
VAMP (Very Attractive Mail Program) is an extremely easy-to-configure, usable, Web-based email client written in PHP3 (and compatible with PHP4). It is for use with POP3 servers, and it also supports "Virtual Domains", encryption (under Linux/PHP3), attachments, contact list, a signature database, an easy-to-use setup tool, and more.
zap is a Perl wrapper for rm, meant be to used by the root account. It checks the list of files passed as arguments against a configuration file to make sure that root doesn't accidentally delete a protected file/directory. The root account(s) should make this script an alias for rm in their .bashrc file.
xtctl is a script for setting/changing xterm properties. It can change the foreground, background, cursor, and mouse colours of an XTerm window, and the icon and background image (only known to work with Eterm). xtctl can also modify the window's title, icon name, highlight background, font, size, position, z-order (raise and lower), and iconified/restored status. There are experimental options for full and soft reset.
djbdns is a collection of Domain Name System tools. Security is one of the primary motivations for the development of djbdns. Every step of the design and implementation has been carefully evaluated from a security perspective. The djbdns package has been structured to minimize the complexity of security-critical code. dnscache is immune to cache poisoning. It is advisable to use the package as a secure alternative to BIND.