Ekphrasis is from Greek meaning the description of a work of art as a rhetorical device. That's actually pretty straight forward, but another way to look at it, is it's highfalutin fan fiction, usually about paintings or pieces of music, but it can be about virtually anything. Look at or listen to the following piece of art and write a piece of prose or poetry that is inspired by some aspect of it.
Today's artwork is...
Seasons by Erik Solheim animated as a gif.
This is a cool animated image which shows a full year's worth of pictures of the same scene. The metaphor potential here is amazing, as is the possibility for description.