my roommates and i are building a table in the fall. one of them is a mechanical engineering major and drew up a design on Solidworks already. his idea has a 'moat' of like 3" pvc pipe cut in half with water pumping in a circle all the way around the table, that way if you get balls back you just put them in the moat and they circle around to the other team, or you can just douse them in the moat if you need to. its a little overkill in my opinion but if he can do it i'm cool w it.
we're also gonna do LED lights that flash to music hopefully and a relatively nice finish.