There has been much speculation about what exactly went wrong with 'Knight and Day'. The film that was supposed to be one of the summer's biggest blockbusters has performed dismally at best. It didn't even win its opening weekend, placing a sad third behind 'Toy Story 3' and 'Grown Ups'. 'Grown Ups'!

So what happened? Aren't Tom Cruise and Cameron Diaz big enough box office draws these days? Sure, Tommy went crazy, married Joey from 'Dawson's Creek' and jumped on Oprah's couch. But didn't everyone forget about that after his zany turn as Les Grossman in 'Tropic Thunder'? As for Cammie D, she's still one of the world's most bankable actresses.