I played the trumpet for 12 years, and I put that down. Also, a less common hobby I have that I also included is my car. I own a muscle car and work on it all the time (mostly out of neccessity), but it is a part of who I am so I thought adcoms should hear about it.
I think it is great to put things down that don't have anything to do with medicine, because it gives them something to ask about in interviews. And then if you think that it relates to medicine you can connect it somehow.