Yamanote walk

A few days ago, somebody told me that one of his hobbies is walking. I told him that I once walked with a friend from Tokyo station to Shibuya station and asked him what his longest walk was. He said that one time in college, he and a bunch of friends walked the whole Yamanote line all night long, starting and ending at Tokyo station. It took them about 10 hours to complete. What in god's holy name are you blathering about? I asked him if they were drinking, but he said they were all sober. When I got home, I looked up walking the Yamanote line and apparently it's some kind of urban challenge that some people do.