Reuse, Refill, Bring Your Own Bottle of Water, BYOB by Rebecca Penmore for 'Do The Green Thing'
My personal favorite: 'The Lone Ranger' used one of these in the vineyards during harvest.
Support the cause, buy the poster...
Hydration with a conscience for Green Day # 256
(* Image of BYOB by Rebecca Penmore from Do The Green Thing's Tumblr)