Many American and British stars who wouldn't deign to do commercials in this country have filmed ads for Japanese products. Some are fairly standard and boring, but most are incredibly weird and very funny.
You can watch them here using a QuickTime player.
Hold your mouse over the letters in the banner to get a list of stars
The Simpsons and Arnold Schwartzenegger did some really weird ads, but Nicolas Cage's commercials for pachinko are utterly hilarious.