This was a new design dilemma for me - a non-working fireplace in the kitchen and SO MUCH SPACE above it. It wasn't even practical space because it was too difficult to reach and didn't seem suitable for storage. What it seemed to need was something very, very large, something way outside of my budget. Instead, I used some chalkboard paint I had left from another project and painted it directly onto the wall. It took about three coats to get the coverage I wanted, but it was easy to do. Then I bought stock molding from Lowe's and took it to a frame shop to have it trimmed and mitered. Then it was on to painting. I primed it, applied one coat of gray paint, and followed it with a coat of white paint that matched the fireplace. After it was dry, I sanded the edges a bit to give it a slightly distressed feel. Then I used finishing nails to attach each piece of molding to the wall.
Since it's basically decorative space, it seemed like the right place to write out a menu, albeit one that doesn't change. If lettering isn't your thing, you can type out letters in your chosen font and transfer it to the chalkboard using graphite transfer paper and a ball point pen. (Transfer paper is available at art supply stores. Just follow the manufacturer's directions.) After you transfer the letters, trace over them with chalk. Voila! Instant "art" for less than $60.