Blogs

Encourage "good" with good office deco...
Take teamwork.
It can be abstract art that conveys a message - "Working together, we move mountains":

Or motivational - "Teamwork is the ability to work together toward a common vision. The ability to direct individual accomplishment toward organizational objectives, it is the fuel that allows common people to attain uncommon results":

(Samples from art.com and successories.com.)