The application may take a while to launch (5--15 seconds) as the graphics are rendered.http://meatfighter.com/j4k2009/coffeeshoppuzzle/
The coffee shop puzzle is a variation of a classic computer science problem. Don't mention which one here to keep it interesting.
Some people can think through the problem and solve it in seconds. Others will remain baffled for hours. Ideally, work out a strategy in your mind and carefully execute it. Don't rely on paper and certainly don't code up a program to solve for you. Post a screen shot if you're the first to solve it. Good luck!