I am a big fan of tennis. It is a sport that has everything I am looking for. It has good one on one competition, requires finesse as well as brute strength, and can be played with a low number of people.
squash, at least on the surface, has those same qualities, though brute strength is needed less. The one difference seems to be about location. In the fine summer months (and the spring and fall, if you don't mind the cold, the giant puddles on the court and sometimes the pile of leaves) you can play tennis outdoors. Squash, as far as I know, always has to be played indoors.
This minor difference really means you have to join a gym, or club, or community centre. While this is not particularly daunting, it does require scheduling that tennis doesn't. You can't just call your friend and say, "Squash in 30 minutes." You've got to call the court, make a booking..... and all that standard stuff. If the facilities are popular, there is no way you're going to get a court on short notice.
Of course you also need people to play with. Most people have a tennis racquet, or could borrow one. The number of people who have a squash racquet kicking around seems much smaller.
I tried joining a league, but there schedule really didn't allow for commuters. I could make later games, but there was no way I could make the early starts. Perhaps there was a way of accommodating my needs, only time will tell.
I would take this one up, it there were some easy way to get it done. (And yes, I know, there is probably an app for that--but then again, there is probably squash on the Xbox Kinnect.