Splitting lunch with a group of friends is always a headache. It's a painful process of recalling old, dusty math skills and trying to meticulously calculate each person's share of the bill. And then beginning over and recalculating when you realize you totally forgot to add the tax and tip into the equation. And if you're with a group of really anal people, hairs need to be split over whose entree was more expensive, who ate the most shrimp from the appetizer and who drank a beer as opposed to water. The scenario brings uncomfortable spine chills.
Then, after all that tedious work, you realize that everyone only has a credit card and the establishment won't split the bill up like that. So one person gets stuck with a $200 bill and a handful of "promises" to get paid back. Chances are good that poor sucker won't ever see his money again. Unfortunately, the restaurant bill simply wasn't designed as a shared burden.
Here's a concept that anyone who's endured a situation similar to the one described can truly appreciate--the Piece of Cake by Jung You Chul, Her Miran, Lee Chang Ho, Lee Kiho and Shin Youngmi. It's a simple multi-card reader that allows each diner to pick out exactly what he ate on the bill and then pay for it with his own credit card. One bill, multiple cards, no annoying math and negotiations.
While the multi-card "cake" aspect is nice, all you'd really need is a touchscreen interface and single card reader so that you could pick out the items and pay your share. Either way, something like this would provide a very pain-free means of splitting the dinner bill--up until you realize you forgot to add the tip in and nobody has any cash. At least you'll almost make it out the door.