I wish we'd had more time (and suitcase room!) to buy goofy souvenirs when we were in Japan. It would have been fun to pick out a bunch of shirts with wacky Engrish sayings -- mangled English that may not make sense, but looks good on a shirt.
Here's a site selling them. This one is my favorite: "Cookie: It gathers with all, and has a party. The time of the snack is happy."