The McDonald’s Breakfast At Any Cost Calculator can roughly determine the best location to fly to to get access to the McDonald’s breakfast menu, based on flight time and whether it will be breakfast time once you arrive.
It is perhaps better explained with an example: it’s 1700h (5 PM) in Tokyo, and you want a McMuffin, but the breakfast menu isn’t going to open for another 13 hours. You can’t afford to wait that long, but where else can you go? The answer, as this tool will tell you, is Honolulu. You’ll arrive around 0616 local time, ready to stride into a McDonald’s and get breakfast. In Tokyo, it’s only 0116, and you would have had to wait hours longer for your McMuffin.
The code is very simple, and the time zone calculations don’t account for DST (since they don’t use the date at all). Flight times are calculated based on latitude and longitude coordinates, a distance formula I got from Wikipedia, and an estimated average flight speed. You can use this tool for times other than breakfast, but it will get confused if midnight lies between the start and finish times.