Walking, with company

It's the only sport here where the stated point can be to talk. There's no pace to match and no level to declare: there's a time, a meeting point, and the wish not to do it in silence indoors.

What these walks are like

Pace separates nobody here
That's the difference from everything else on this list: on a walk the group sets the pace as it goes and nobody gets dropped. It's the easiest thing to join without knowing anyone.
Duration does
Forty minutes after lunch and three hours along the coast are different plans. It's the one thing worth checking before you join.