The only reason anyone would want to know anything of your extra-curricular activities is to show that you are well rounded.
Team sports are good, as it shows you are interested in keeping fit, and a good team player which is what they're looking for in a multi crew operation.
Any sort of volunteering, scout group, youth club whatever would show you are interested in the community and so probably aren't a total dick, again a big personality will not fit well in a small cockpit.
Also showing you're an interesting guy, I for example play a musical instrument, gives you something to talk about on those long flights. At the end of the day you have to get invited to interview first, but at my interview the above topics were certainly discussed at length, I'd say far more than any technical aviation questions since you already have all the bits of paper saying you know what stuff.