In addition to the yearly [Perl Advent Calendar]( from Jerrad Pierce, originally started by Mark Fowler, the Catalyst Team have put together their own [Catalyst Advent Calendar]( Each calendar gives a new tip or trick or module to use each day. [Today's tip]( on the Perl Advent Calendar is about how to use IPC::Filter to communicate between processes, while [yesterday's entry on the Catalyst Advent Calendar]( discusses how to create PDFs for your web application.