One pretty cool use for Perl which I have been involved with recently has been the design and implementation of the integration software for the Optus Message Board at Federation Square in Melbourne, Australia - See here
for details about the upcoming official launch on the 19th November. This Message Board allows visitors to Federation Square to send SMS messages from their mobile telephones and have their messages displayed on large, colour LED text displays attached to the East Shard building in Federation Square.
Introduced to this project very late in the picture, the use of Perl has allowed the company that I work for currently (The Swish Group) to develop a cross-platform solution - This was particularly important as there has even been an installation platform shift since the original RFT response was provided - drawing upon some of the hallmarks of rapid application development project methodology. The role which Perl has played in this solution is two-fold - Firstly, Perl was used in the form of mod_perl and SOAP::Lite to develop a web service interface for message receipt and routing (to which a .NET client connects from the SMS message gateway). Secondly, Perl was used to build an event based engine (using Event.pm rather than POE because of it's lighter overhead) which connected with each of the LED text displays, polled their current status and communicated new messages for display. Connecting these components together is a backend database (MySQL) and web-based administration system which serve as the persistent store and management interface for the integrated system respectively.
Visitors to Federation Square should take a look at this Message Board if they get a chance as it is an excellent example of how Perl can be used for integration solutions in unusual settings. Messages can be sent for display using the telephone number 19 SMS FED (19 767 333)
perl -le "print unpack'N', pack'B32', '00000000000000000000001000000000'"