JuMiLDAP is a simple Web-based LDAP address book viewer. You may browse contacts, search for them by name, and assemble address lists (e.g. for holiday trips).
LDAP Address Book is a Web application for browsing and searching contact details within an LDAP directory. It supports Microsoft/Samba Active Directory and Novell eDirectory.
A Live Linux distribution with a focus on education.
An easy to use, but still quite capable firewall for Netfilter/iptables.