Grab the nearest book to where you are - open it to any page. Take the first full sentence on the right hand side. Randomly select another page and take the first full sentence on the left hand page. Go to the end and get the last sentence of the book.
Write for 10 minutes using these sentences; or the essence or core of these sentences. Or write about the first time you remember being excited about something as a child: what did it look like, feel like, smell like - why was it important?