They are in the smallest city in professional sports.  Ohio State's football stadium can fit more than the population of Green Bay.  Despite this, they have a waiting list for season tickets at Lambeau Field that has over 70,000 names.  People who got tickets in 2007 waited about 35 years for tickets.  Due to the growth of the waiting list and the rate that people on the list get tickets, it will take over 70 years for some people to get tickets.

The team is owned by some of the people on that list—the approximately 100,000 shareholders that own the team get no special preference for season tickets, they receive no dividends for their investment, and the stock cannot change in value.  It is actually against the NFL rules for a team to be owned by more than 32 people, and one of them has to own a large share of it.  Green Bay's ownership was established before the rule, so they were given special consideration.  Therefore, no other team will ever be owned by such a large collective of fans.  In fact, the Packers were in the NFL before it was called the NFL. 

Their long history is another part of what makes them the greatest franchise in sports.  The Packers have 12 NFL Championships, more than any other team.  Included in that are the first two Super Bowls and the 31st.  Lambeau Field has sold out every game since 1960, and a Packers game at Lambeau Field is an unrivaled experience. 

There are many more reason that the Green Bay Packers are the greatest franchise is sports, but some need to be experienced to be understood.  So for anyone who has not been to Green Bay on a Sunday afternoon or Monday night during football season, GO!  It's something that every football fan needs to experience at least once.  And if you're really hardcore, go in December or January.  Despite the loss of Brett Favre, I firmly believe that the Packers will be playing games in January for at least as long as Thompson and McCarthy's contracts.