Grab a pen or pencil and a large sheet of paper, close your eyes and start drawing. Think about anything you like but keep that pen moving at all times. Perhaps play some music and marry the feel of the sounds to the gestures of your mark-making.
Don’t open your eyes until you’re finished with that drawing. Scan in the drawing, chop it up, add more to it, whatever you like, don’t be precious. Surprise yourself by creating something you didn’t really know you would create.