Go to an art museum or gallery - take a note book, don't look at just what you think you should but what your mood draws you to see. Write down what emotions you are feeling, and ideas as they come to you.
Listen to music - sit down, relax, and listen to the music attentively. What feelings does the music inspire in you? How can you harness those feeling into a project you are working on?
Visit a craft store - check out supplies in your medium, as well as supplies in a medium you would like to try. Look at them with a fresh perspective, let the supplies inspire you.
Doodle - doodling is a great way to release your inner critic and let your hands draw free.
Explore you fantasies, daydreams, and visions - ideas can often arise from the bizarre images in you fantasies, daydreams, and visions. Take a few minutes and journal about you fantasises, and the ideas that come to you.
Play with toys - pull out some children's toys, or crayons, or play-doh, and take a few minutes to let your mind relax and be open to new ideas.
Take a drive - when you drive you can't do anything else, so use that time to let your mind wander discovering new ideas. Listen to your inner voice.
Try these activities over and over again. Do them alone or invite a friend to get their reactions and share their ideas.
What are your favorite thing to do to recharge your creative battery?