Warner Bros. has launched another viral Web site for their Batman Begins sequel The Dark Knight at www.whysoserious.com.

Yesterday, the site contained a hidden trailer which could be watched on the site or downloaded in high definition. Today, the teaser is up on the front page. Note, there’s no footage from the film, only dialogue.

Also, yesterday the site featured the official Gotham Police Department report on The Joker, which today appears to have been “hacked” by the Joker. (Forgot to take a screenshot yesterday!)

As previously reported, two other sites viral Web sites have also gone live, that contained clues for hidden messages and images.

AICN has posted a new image from movie of Heath Ledger as the Joker holding a knife up to Rachel Dawes (played by Maggie Gyllenhaal). See image here at top right.