On my midterm, I leave the back page of the exam blank. It's intended to be used as scratch paper, for students to work out the more difficult problems. But, every semester, I put the following in the center of that page:
You may use this space
To organize complex thoughts
Or for a haiku
About 1/8 of the students take the time to write an actual haiku in the space - most are silly, some are very clever, and a few are really beautiful. I've noticed over the past few years that the students who take time to write a haiku score about 10% better on the exam than those who don't.
Take time for poetry, and other creative activities. It does good things to your mind!