Search::Xapian is a Perl XS frontend to the Xapian C++ search library. It is a fairly complete wrapper: most features of the Xapian library are made available for use from Perl. Xapian is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model as well as a rich set of boolean query operators. It's fast and scalable to hundreds of millions of documents.
Config::Maker takes a file with data in simple hierarchical format (similar to BIND and DHCP configuration files) and several templates, and produces the text by filling in the values. It is mainly useful for creating related configuration files. It can be used to generate firewall configuration scripts, DNS zone files, DHCP configuration files, a reference from a single file with all users and machines, etc. It's useful when you are not satisfied with keeping information synchronized in several places, but don't want something as complex as cfengine. Snippets of Perl can be used if all else fails.
Audio::Xmpcr is a Perl API to the XM PCR Satellite radio. It offers two different operating modes (direct and remote+daemon) via a single interface, continuous device polling for instant, accurate song listings, auto notification when songs change on any channel, and a few utility programs including a Web interface for remote control/listening to the radio via icecast, a stream ripper that divides songs up into properly-named wav files (for making MP3s), and a finder that searches channels for the song(s) wanted, and records just those.