This came from a A Winter Veil Gift under the Winter Veil tree in 2012. It looks like a little football/American soccer ball. If you target a friendly player and right-click the item, your character will kick it to them and they will kick it back. The present it comes from can also contain The Pigskin instead, or in addition to, your foot ball. If you get both (either across multiple characters or on the same one), you earn the achievement They're Both Footballs?
In Warlords of Draenor, this item will be added to the new Toy Box feature and no longer take up a bag slot. You will be able to "use" the item straight from the Toy Box interface.
The Toy Box will be account-wide and therefore so will this item.