A clever way to make dropping spare change on a coin bank interesting is to turn it into a contest. The Duel Savings Bank does the idea one better, allowing you to keep track of who's leading using simple physics.
Designed by some bloke named Ding 3000 (and, no, I don't think dude's a robot), the half-circle coin bank is designed to stand on the curved side, with two coin slots on the flat top edge. Each slot sends the coin down to different inside compartments, situated on either side of the container. The more coins you add to one side, the more the entire structure will tilt there, showing the disparity of contents in plain sight.
The Duel Savings Bank is a white porcelain container, with a surface that can be easily written on with a marker and erased with a clean cloth. That way, you can mark each side with any label you want. Edges are made from a red silicone band, with a slide-off panel, so you can quickly cash out without having to break the damn thing.
It measures 6.3 x 2.4 x 3.5 inches, so it's small enough to not take up much space in the coffee table, where you can watch it tip over to your side all day long. Remember, though, the coin bank can be easily relabeled and the coins can be quickly switched into the other compartment, so keep a watchful eye on it, lest risk having your competition cheat.
You can get the Duel Savings Bank from Sleek Identity, priced at $39.