There were. Besides having them on the airbases, we played in a court in London that was on the outer band of the tube system. It was a very nice court - the only place I ever played that had a proper viewing gallery above the court. I remember clearly one of my two tournaments there. After being trashed by my own trainer to move into the loser’s pool, I beat a Polish entrant in a very close match (I nearly lost after building a nice lead), then was beaten in another close match by an Irish Martina Navratilova lood-alike. My best outing ever. My partner and I actually made the quarters in doubles until again facing my trainer and another player at his level. I would have fired him, but he was an officer on my base (I was enlisted) and he was training me for free. 
Personally, basketball. But it helps that I’ve played for years, am really tall, and can jump high enough to make it over most household furniture.
In general, I think a person applying themselves could most easily move up the ranks in a sport like distance running. There isn’t a ton of physically specialized moves needed like most sports. The hardest thing would probably be centered around the discipline of changing diets and sticking to a ridiculously hard training regimen.
I wish I could say cycling, since I love all kinds of it, but you don’t see too many 200 + lb pro cyclists in their 30s. I’d go with** drm** and say powerlifting - not my favourite sport but I lifted for about 3 winters and reckon I’m a good natural fit for it. I was putting up over 1000lbs across the 3 lifts just messing about. If I did it properly with training / coaching / eating right I reckon I might have some potential. Pro would be out of the question (how many professional power-lifters are there?), but nationally competitive might be attainable. Maybe not in the combined event as I sucked at the bench, but the squat and the deadlift came pretty easy to me.
To be honest, I reckon most big guys could do OK powerlifting - there’s not a great deal of skill to it relative to other sports. It also seems to be a good sport for more middle-aged people to excel in.
I probably could have been a punter.
Beyond that, I’m too small to have been a football player at any other position, too short to have played basketball (I’m better at basketball than at any other sport, but I am not a ball handler / shooter, and I’m only 5’11"), and too awful to have played baseball.
I’m a pretty good golfer with little to no effort. I play once or twice a year. We just had our tourney at work and between last year and this year, I had picked up my clubs once. My team came in 4th with -8. By team, I mean it’s a Captain’s Choice scramble, but I am ranked as a B player (for our tourney) and about half of my shots were played. If I put some effort into practicing, I think I could be very good. It would be my only hope to be professional athelete.
I suck at every and all sport. I suck least at golf.
Nope.
It’s sports-entertainment. 
Before I hurt my shoulder badly it would have been volleyball. Also, at one time I was a fairly serious paintball player (and yeah, they have professionals in it and it’s a sport :)).
Today however I wouldn’t have a shot at even professional computer gamer…reflexes are shot, getting old, fat and bald.
-XT
NFL Placekicker. Based on absolutely no evidence, except it doesn’t look that hard.
Would you consider body building a sport?
No, I’m not cut right now - nor have I ever had that type of bulk, but that seems to be one “activity/sport” that I could have a chance at participating at given my lack of any god-given ability in anything else. I’ve often thought bodybuilding was one thing where through dint of effort alone just about anyone could work themselves into shape to compete at a pretty high level. And there are age group competitions as well.
Paintball, but I don’t play a lot any more. Too expensive. 
I would consider bodybuilding based on “physical skill”. And no, it’s not really something that can be done through enough effort, a lot of it has to do with genetics. Some body types just look better. Some people just naturally have better symmetry and balance than others. Some people can only look good with a LOT of effort and some can look great with little effort. And yes, there are age classes and weight classes.
That said, Bodybuilding would probably be my best bet. I already have a good physique and symmetry from my current workout. If I tightened my diet, geared my workout a bit differently, and did a lot of practice with posing, I would definitely be able to compete.
Some backups would be billiards or video games. The first, I’m pretty good, but I’d just need to practice several hours a Day rather than shooting an hour or two a week. As for the latter, I’m already pretty good, but don’t play as much as I use to, so I’d just need to get in the practice again.
Soccer: I’ve played at a very high amateur level my whole life, and have played on the field at times with local pros and ex-pros without total embarrassment. My ankles are too old and have too many past sprains to hold up to regular punishment or training though…so the only chance at glory would be for me to time-travel back to 1943 and qualify for the officer’s POW camp team, and play a match against the German nationals to embarrass the fuhrer.
Tennis: High school varsity, and beat a Div 1 college guy in a practice match once. So, with the proper headband and visor, and a grizzled old coach to guide me, maybe I have a shot?