What about starting a Random Acts of Kindness movement? You start (maybe get a few others involved) doing things for other teachers along with leaving them a note encouraging them to do the same....
One year we had two little baskets that traveled around our school (staff list attached to it) where you pick someone to fill the basket for--fresh cookies, a novel, a coupon for a movie rental/box of micro pop, a little plant, etc---put a little note on it about bringing cheer, etc. and asking them to spread the joy by filling the basket for someone else. If they don't wish to participate, they can just return the basket to you and you can find another staff person on the list to start it again.