Random Idea Generator: Find a magazine and scan the table of contents for the titles of the articles. Often, writers use unique and interesting turns of phrase. Choose one and use this is a jumping off point for a song.
Conversation Starter: During your next conversation with someone, LISTEN! You'll be surprised how often people have interesting ways of expressing things and unique perspectives just in every day conversations. Take one thing they said and run with it. Many great songs have been inspired by the simplest of discussions!