G: Go out for lunch
Leave the office and meet a friend for a quick change of pace and scenery. Eat something light so you don't go back to work feeling sluggish and unmotivated. And avoid alcohol -- it is a depressant, after all.
H: Hike or bike your cares away
Give stress a one-two punch by getting out and working out. Communing with nature is a natural mood booster and the endorphins produced by vigorous exercise will have you feeling on top of the world.