What is engrish?

What is Engrish? According to the site it is well defined as the humorous English mistakes that appear in japanese advertising and product design. Engrish can be found all over the world, but the vast majority of the really funny and creative Engrish is from Japan.
What would you think if somebody just asked you to "eat their house", only to find out that you have just invited to lunch or dinner. Some non english speaking countries have included english in their primay schools curriculum and have had it listed as a second language, but if you have no one to practice it with then the knowledge is lost. In Japan's case, it is used in advertising as a way to give them a modern look and feel even it sounds funny.