Do universities (especially Ivy League) look at what you do during the summer?

When you applied for a university, there isn't a question that specifically ask what you do during the summer right? You can just put your transcript, awards and achievements, volunteer hours, etc or basically whatever you want? So, I can just get a like a retail job or just hang out with friends during the summer and if I get outstanding national awards and high grades, there is a chance I can get into an Ivy League? So, what you do during the summer can be kept confidential? And by the way, I'm just a high school freshmen, wanting to be a surgeon. Do you think working/volunteering in a health-related field is allow at age 15 or 16? Got three more years to figure out this college thing. And which Ivy League is good for a future medical student? Any tips or advice is appreciated. Thanks =)