Seattle...losing their NBA team and getting burned by the refs in the SuperBowl. No way Houston can top that...
rf83 makes a good point. I was thinking a sports city to be unlucky if they haven't had good teams. But are you looking for "unlucky city because of bad teams and events" or "unlucky TEAMS" ? The former was why I chose Cincy If it's the latter, then I won't count Finals appearances and WS appearances as positives necessarily if the team ended up losing in an unlucky way..
I was sort of doing it for both. I mean which would be worse to you as a fan having a team be horrible forever or have a team that continually shows glimpses of winning a championships only to break down or have them stolen from them? That is sort of the reason for some of the places, such as San Fran/Oakland area which has had some success only to have it blow up in their faces. In hindsight, I realize now that with the dates Denver is probably not the best option.