One of the funniest sites I saw when I first visited Switzerland were the open-air chess games that went on during the warmer months. For an outsider, this was completely fascinating because I had never seen anything like this in North America before.
I think what is more entertaining is just seeing everyone who is around the entire game while two people play with life size pieces. I've only seen a few areas where these venues actually exist. I've come across one in the grand park in Geneva, one in Ouchy and another in Bern but that is about it. I really wonder what the obsession is about.
I guess it's a great past time for some Swiss but I've heard that its more an obsession from the Italian speaking area and beyond. Games such as bocci ball are also played to this degree. Personally I can't stand chess but maybe that's just because I never bothered to learn the game. I loved checkers and was checkers queen and that was enough.