Less Wrong is as a community extremely nerdy. That's true for almost any definition of "nerd" that captures anyone's intuition for the word. However, to a large extent, many aspects of nerdiness are not connected to rationality at all, even though nerdiness may be associated with more rationality in some limited aspects. For example, fantasy literature is probably not in any deep way connected to either intelligent or rational thinking except for historical reasons.
Yet LW is full of references to science fiction, fantasy literature, anime and D&D. In one recent example, a post started with an only marginally connected tidbit from Heinlein. Moreover, substantial subthreads have arisen bashing aspects of other subcultures. For example, see this subthread where multiple users discuss how spectator sports are "banal" and "pointless". I suspect that this attitude may be turning away not only non-nerds but even the somewhat nerdy who enjoy watching sports, and see it has harmless tribalist fun, not very different than friends arguing over whether Star Wars or Star Trek is superior which has about the same degree of actual value here.
There's a related issue which is a serious point about rationality and human cognition: Our hobbies are to a large extent functions of our specific upbringings and surrounding culture. That some people prefer one form of fantastic escapism involving imaginary spaceships isn't at some level very different than the escapism of watching some people throw and catch objects. Looking down on other people because of these sorts of preferences is unhelpful tribalism. It might feel good, and it might be fun, but it isn't helpful.
So I have, for a while now, had ideas for a couple posts about rationality that use sports as the source for most of the examples. Spectator sports are actually a rich field for rationalist analysis because they are rife with irrationality and there have been a number of recent developments in fixing that. I think sports fans, athletes, coaches and analysts could learn a lot from us and we could learn a lot from them.
Maybe I'll write one and see how it goes.
Incidentally, the way I got into sports (basketball in particular) was by discovering it as this big mystery- where I wasn't quite sure what factors at what degrees were involved in winning. Part of the reason I haven't gotten into baseball is that it's almost a solved problem at this point and I haven't gotten involved in football as it appears to complex for the low-hanging statistical fruit to be of much interest.
I have found being a big sports fan excellent practice for noticing and avoiding tribalism and motivated cognition. I highly recommend it.