We have a small nook area on one side of the kitchen that took us a long time to decide what to do with. The space was designed for a small kitchen table but since we use the dining table for all eating, we wanted to use this as a designated Montessori activity space for the kids. The space has great lighting (west facing, big window), laminate flooring (easily cleanable), and is inviting.
In terms of furniture, we added a side cupboard and some higher cubbie shelves for art supply/activity material storage and otherwise left the space open. Since the room was open to the main hallway, we also added a barn door, which slides against the wall to take up minimal space and add some visual interest, as well as blocking sound. We hung some local :) art on the wall and found a second-hand easel for our artists.