I just got back from Toronto a little over a week ago, dammit. NOW you tell me. 
High-stakes amateur street football (WARNING lots of swearing).
Vice did a great 6 part series on the street bowl championship.
I figured there were pickup games of football being played all over, but I didn’t realize there was an extremely competitive, organized league of street football played by teams from all over NYC. Street football is a simplified version of normal football, allowing for it to be played on smaller fields.
I actually prefer duckpin far more then ten pin. Probably because I grew up playing it more, though it is a lot tougher and that makes it more interesting too. I was on a duckpin team about 15 years ago, if I had the time I’d think about going back.
There are leagues for swimmers that I didn’t know about until 15 or so years ago when I came back to swimming after 10 years off. There are meets around the world as well.
My son played on a wiffle ball league.
I was once in a handball league.
Cornhole (which is like horsehoes or lawn darts with bean bags) has a national organization with local leagues and tons of tournaments. Their world championships were even featured on ESPN last year.
MAJOR LEAGUE DREIDEL
http://www.facebook.com/NTL-National-Tiddlywinks-League-127827130612316/
And, though it’s not something you could make a league for, how about
http://www.worldconkerchampionships.com/html/conkers_rules.html
Not exactly a league, but Magic: the Gathering (a collectible card game) has had a Pro Tour for twenty years now.
I’m a proud member of the Moustache & Beard Social Club, one of the oldest organized groups of beardsmen in North America.
We are affiliated with the Facial Hair League.
Cool! I’ve met some of your bearded buddies. A friend of mine has photographed the National Beard and Mustache Championship and I’ve met a few competitors. It’s a small (hairy) world.
Not the existence of leagues since they’re pretty common in Spain in the summer, but the location: boules in Sweden. My English coworkers were stunned that there was such a thing anywhere.
I’m obsessed with the subreddit the ocho which features all sorts of obscure sports, many of them deeply competitive on levels I previously never imagined.
Heh… do you guys have rabiosa championships (hoe throwing) and goitiberas? The commercial ones depicted there are quite close to the classical “grab half a door or a chunk of fence and add wheels” models.
Indeed it is. We have a number of past national and world champions in the club. Mostly they’re just good drinking buddies though. We do some good community works and have a good old time.
I recently found out that there is a professional ultimate Frisbee league. And you can have a professional ultimate fantasy team