The activity doesn't need to be a sport or something you get skilled at. I like to take walks to a park near my house, so when I went out there with a girl it was fun for me, we had good conversations, and nothing was "flushed down the drain" as you say, even though I never saw her again.
The last thread didn't fare too badly, I think; let's make it a monthly tradition. (Me, I'm more interested in thinking about real-world policies or philosophies, actual and possible, rather than AI design or physics, and I suspect that many fine, non-mind-killed folks reading LW also are - but might be ashamed to admit it!)
Quoth OrphanWilde:
Let's try to stick to those rules - and maybe make some more if sorely needed.
Oh, and I think that the "Personal is Political" stuff like gender relations, etc also belongs here.