There's been a lot happening since I last updated on this project. $60 will get you a digital copy of the art book, plus everything from the previous tiers. $100 now includes everything in the previous tiers (including the digital art book) plus the game in an old-style big box (like the ones the LucasArts adventure games came in) and an Adventure backer T-shirt. If you have the money to spare, a $500 tier is also available with a hardcover version of the art book, signed by Tim Schafer, plus all previous tiers (except for the signed poster).
At 3PM PDT, there will be a celebration with Double Fine as they countdown the final minutes of the kickstarter campaign at http://www.ustream.tv/channel/double-fine-adventure (Tim urges that you don't refresh the kickstarter page in the last few minutes and view the video instead).