One of the things I love about it is that we ALL (that is, all ages, all ranks, and all MOS) go out on Friday mornings, throw heavy packs on our backs, and traipse around Lake Quannapowitt.
For the record, I really believe what they say about team-building through shared suffering...but this definitely isn't suffering. It is, however, a shared and collective experience -- undoubtedly, as we remember doing it years from now, the air will have gotten colder, the snowdrifts higher, and the wind nastier every time the stories are told.
With this Friday being a holiday, that makes tomorrow the 'ruck' day, which means I won't even have to think about the snooze button.
I don't know the office-place equivalent, but whatever your 'group' (say, your company, your family, your block association, etc.) a regular -- even if infrequent -- activity can be a great way to build some tradition and shared memory.
And if even people grumble about it, they might not 'really' mean it..