That might be fun to mention in an interview but, IMO, that is stretching it for an application. I also think if you are stretching so hard you need to take a deep breath. Most of the kids who are applying to these schools are talented and interesting, trying to show how quirky and unique your kids are is going to fail.
(I am not even sure there is a space for hobbies in the app, the ones we did did not have that kind of space. It had a section for ECs and I would not count rubics cube as an EC)