I was selected to be part of a hackathon in Grenoble, France as part of Plush and Nugget's workshop on "the study of play." I traveled to France in January of 2018 and sat through a few days of workshops to learn about the theories and studies of play and fun and how people interact in "fun" and delightfully surprising ways with objects. 
After learning, we were set free in teams of 2-3 to "hack" everyday objects to make them fun. 
My team had a chair to hack. We turned the chair into a light-up rocking chair with a surprise collaboration element to it. I was the only MechE on the team, so for the 2 days of the hackathon after brainstorming and concept-forming I was in charge of prototyping and eventually making the product. I used a jigsaw to carve rocking arms out of dimensional lumber and attached them to the chair. My teammates were a design major and an EE/CS major - they were in charge of final aesthetics, and the electronics. Over the 2 days of "hacking" we not only all completed our respective parts of the project but spent a considerable amount of time teaching each other how to execute in a different role. I taught the designer (who had never touched power tools before) to cut with a jig-saw and paper prototype, and she finished one of the chair legs with me. And I got some practice in the Arduino environment, and learned how to approach problems from a design mindset.  
The chair featured an arduino-driven LED system that slowly pulsed/glowed when nobody was sitting on it to invite someone to sit on it. When they sat on it, the chair detected motion through accelerometers and translated that acceleration and motion data into a visualization of the rocking motion along the axis of the two LED strips on the sides. The person could sit and rock, and everyone else could see them rocking and see the chair understanding the rocking. 
What's better is there was an "invitation" on the back in the form of foot-prints on a back pedal that asked another user to engage with the product by stepping on the plank and thus jerking the seated-user backwards. People had SO MUCH FUN rocking each other, and surprising the unexacting victim by jerking them backwards. 
This was the full group of people invited to the hackathon in France. We had students from all over Europe, MIT, and professional mentors as well as a full fab-space. We had a lot of fun, and of course played a lot. 
And here are some photos of us in the workshop, some of our early chair concepts, and then the construction of the chair. Testing was a blast, and we had as much fun making it as we did playing with it in the end.