This is still a work in progress but I think it's neat. It still needs caching and proper error handling. I would welcome any feedback.
Because it uses the same words and short phrases as the lyrics it consumes, it just seems like a mishmash. Maybe you could substitute synonyms or words from the same class (e.g. August instead of April). Another great thing would be if it considered the number of syllables per line [does it already do this?] and follow a pattern from one of their songs.
I like the idea of counting syllables and possibly implementing a sort of structure to it with choruses and whatnot also. Would be cool to enforce rhyming too.