Here's a way to mix it up for high-interest writing.  One day each week, incorporate music into journaling sessions.  Many  times, the overall mood of the piece can inspire creative free writing.  Use specific songs and artists to generate thematic entries, and students also love the opportunity to incorporate artwork, like designing album covers (you may have to show them an album or a CD cover!) or a music video storyboard. You could even have a parent send in a favorite song from his/her childhood and have the students guess which of their classmate's family the song is from.