I first read about the practice of Japanese using English words that made sense to them but to nobody else in Confucius Lives Next Door, a book written by a former Washington Post bureau cheif who got posted in Japan for some years. As I recall, the one he thought most amusing was a sign that read "Let's Sex!" above an ice cream shop. The author explained that these things happen because a) the Japanese love most things American and b) they tend to pick slogans that sound phonetically like Japanese stuff.

It is because of this that I won't put oriental symbols on anything I own. It's nothing personal, I swear. It's just I have this sneaky feeling that I would end up with "Stupid gaijin doesn't want to be bothered to learn Japanese. Let's Sex!" stamped on the back of my t-shirt.

Anyway, this stuff is extremely funny. We're talking laugh-out-loud here. An example:

MR. FRIENDLY: HE ALWAYS STAYS NEAR YOU AND STEALS IN YOUR MIND TOLEAD YOU INTO A GOOD SHITUATION (found on the side of a wallet)

However, the site is a bit slashdotted right now, so it may be quite slow. Be patient, it's worth it.

Engrish.com