Technorati has a service that will generate an iCalendar file from any webpage containing hCalendar microformat entries.
Welcome to the world of "Web Pipes"...
What is a "Web Pipe"? A "Web Pipe" is a term I coined to describe a Web resource that takes the input from another resource and consumes it to produce something else... much like a Unix Pipe. Web Pipes only use GET, and must be formed by concatenating multiple URLs.. for instance http://feeds.technorati.com/events/http://microformats.org/.
A Technorati hCalendar "Web Pipe"