Filk is a subset of folk music that is practiced in, by and for the Science Fiction and Fantasy community. The term 'filk' was originally a typographic error in the program for a science fiction convention and the term stuck. People who write or sing filk are 'filkers'. In its earliest form, filk was the setting of new, usually humorous, words to old tunes. Filkers still write new words to existing tunes, but they also write songs that are original both in music and lyrics. These songs can be funny or heart wrenching, silly or deadly serious, or someplace in the middle.