microformatique - a blog about microformats and “data at the edges”

In a similar vein to Optimus, and a number of other microformats parser is Cognition, by Toby Inkster. Congition goes beyond parsing just microformats -

Cognition is a parser for both “upper case Semantic Web” (RDF, RDFa) and “lower case semantic web” (microformats) technologies. It includes modules for exporting parsed data in a variety of formats, including RDF, vCard, iCalendar, Atom and KML.

Cognition is written in Perl 5 and released under GPL3 - so if you are looking for a parser as part of your app, check out Cognition.