It depends on where you live. Where I live there are a lot of non-school leagues for just about every sport and every age group. There is also a wide range of the competitiveness, from the "Show up to just play and have a good time" (aka Beer Leagues) , to the very competitive ones. While yes, most of the competitive sports are tied to schools, there are lots of recreational sports leagues for anyone and everyone around the US.
I love sports! Over the years Ive played football, basketball, baseball, skiing, hockey, golf, and I even tried snowboarding for a year (bleh! )
Sadly I just finished up high school football and I will miss it dearly. So now I ski, run once and a while, and weightlift.
It pisses me off when I see people wearing those T-Shirts. All of those people who wear those shirts don't know that he was a mass murder and a ruthless killer who wasn't afriad to knock off anyone who got in his way. Inspirational revolutionary my ass!