I’ve been playing the Google Da Vinci Code Quest. The first 10,000 people to solve them all (and also enter their submission form) will get a cryptex (which I imagine a lot of them will end up on eBay). I don’t think they’re too worried about people “cheating” since all the questions are practically the same for everyone. So, several cheat sheet sites are available (see below). It seems like what it’ll boil down to is how fast you can do the last problem (which will be this Thursday).
I don’t particularly like the chess problems since they are not the classical “mate-in-3” type chess problems where there is really only one possible solution. No serious chess player would make those type of moves. So, knowing how to play chess does not have much advantage. But, I do like the soduku and hanging artwork problems where it does require some thinking. The rest of the problems basically involve how well you can do Google searches.
Cheat Sheets:
Student Rant
Googlefact
ozphilc