Last year volvo did a promotion for Pirates of the Carribean that involved an online puzzle treasure hunt. You had to sign up and then recieve email clues every few days. You would us these clues to solve a puzzle on their website. At the end of the month, when the final clue was revealed, the first few people (I think they took three people from a few different continents/areas) to solve the puzzle would travel somewhere and compete in puzzles to win a volvo and some cash.
I did it last year and it was pretty fun, though the puzzles were hard as shit! Its all flash based puzzles. I cheated and peeked on forums that were discussing the answers for most of them.
They have just started it again for the release of the next POC movie. I know that I have 0 chance of winning the thing, but I'll play along until they get too damn hard. I've just started the second puzzle tonight.
I know there are many here smarter than I, so if you guys want to give it a shot, it'd be fun to discuss the puzzles here. Check it out!