You may be at a point in your life where splitting the bill comes off as tacky, but everybody's been in that position where it's totally necessary. For those times, like college, the Go Dutch Bill would come in super handy, if it actually existed.
The Go Dutch Bill is a concept by Szu-Yu Liu, up for the 2012 iF concept design award. And when it comes to designs, it has a pretty good one. The perforated bill lets you easily divvy up the check person by person, and even has a handy little flap for clipping your piece onto your cash or credit card.
As cool of an idea as it is, there's probably no way it would ever catch on. While cool, it's not that much of an improvement over totally separate bills, printing such an irregularly shaped piece of paper would be tough, and any shenanigans that involve sharing an appetizer are still weird. In fact, the Go Dutch Bill would have to have some kind of weird no man's land for those cases. In this day and age, a digital solution is probably more elegant.
Impractically though it may be from an implementation perspective, the end functionality is at least neat, and would have saved me a lot of time miscalculating and re-miscalculating separate balances half drunk at restaurants in college. Some things just aren't meant to be, but I kind of wish this one was, if for no other reason that the deliciously bad "split the check" puns. [Yanko Design via Technabob]