Goodia has launched an easy-to-use free iPhone app that allows you to experience and enjoy such a gyudon restaurant from the "making" side.
Its name is "Donburi Dojo"! A game in which meat is placed on beef bowl and pork bowl, then sorted into each, and the time is competed to see how quickly all the bowls can be made. World rankings are also available, so you can compete with users around the world for gyudon making skills!
If you do it when you are hungry, you may want to eat something more and more, but sometimes you can easily use it to kill time in the mood of the provider.