I enjoy working on projects that mix art, engineering, science, and the occasional flame tornado. Here are some examples.
Dr. Brainlove is a climbable, interactive, 15 foot tall brain jungle gym mounted on a modified school bus, with lighting controlled by EEG and neural models. It combines educational outreach, a 3d printed space frame, and computational models of the brain into one loveably crooked-eyed vehicle. Check out the Indiegogo page, and the Facebook group.
Syzygryd is a multi-ton musical instrument played collaboratively by three people.
More information (and gorgeous pictures) at http://www.syzygryd.com/.
Grad school would be incomplete without building a Ruben's tube, and testing it ... indoors? See standing waves made out of flames.