Can giraffes vomit?  If so, do they have any special adaptations, postures, etc. that allow them to do this more easily?

As ungulates, giraffes throw up on a regular basis. Not like you and me, but more like a cow that brings up cud to be chewed. The mechanisms are the same as in other ungulates, just stronger. Peristalsis (the coordinated contraction of smooth muscle) that moves food down the throat is reversed to bring the bolus of cud back up again.