Hockey rinks are often called money pits. They're really expensive to operate and they only tend to last about 25 years before running into major mechanical issues. And yet, there's this company called Black Bear Sports Group that spent the past decade going around and buying them up.We just spent several months reporting on the business of youth sports, specifically youth hockey. And one of the things that we learned is that even though hockey rinks are difficult businesses, they're also a finite commodity ...