What is filk?

We aren't sure how to define it exactly, and neither is Wikipedia. According to Wikipedia:

One definition is based on filk as a genre: filk is folk music, usually with a science fiction or fantasy theme. But this definition is not exact. Filkers have been known to write filk songs about a variety of topics, including but not limited to tangentially-related topics such as computers and cats. The other common definition is anthropological (and recursive): Filk is what is sung or performed by the network of people who originally gathered to sing at science fiction/fantasy conventions. Yet another definition focuses on filking as a community of those interested in filk music and who form part of the social network self-identified with filking. ... the origins of filk in science fiction conventions and its current organization emphasizes the social-network aspect of filking.

Filks Available Here!