Isolation and polarization are big threats today.
We can't take collegiality and community for granted. We have to work steadily at renewing them.
Part of the requirement of leaders now is to recognize that times have changed. We must strategically work to create these essentials that in times past seemed to come naturally.
So here's a marvelous collection of blog posts on team building on Human Resources Today. I particularly like this group of teambuilding exercises.