If you find it necessary to create some type of art for your classroom, maybe you should try BigHugeLabs. This site has some great project options for you. It offers projects like the motivator you see illustrated here on the page. You create movie posters, jigsaw puzzles, badges and much more. The best thing about it is, that it's free. Every teachers favorite price.
A Grading Strategy
If you are looking for a tool to help your students collaborate or brainstorm ideas, try padlet. Padlet is similar to pinterest and its free. Padlet allows users to express their thoughts on any topic in any format available. (e.g. images, videos, documents, text), anywhere, and on any device. You can also costumize the padlet with beautiful wallpapers and themes. Each padlet can be shared with specific people or to the world and its edited in real time. This is a great tool to get your students to work together. Take a tour here: padlet.com