DS hacker reveals a total of 27 weekly puzzles, unlocked by downloadable key.
Due to the work of some clever DS hacker, it has been revealed that the weekly downloadable Professor Layton puzzles are not really being downloaded. These bonus puzzles are actually already contained on the cartridge. Every Sunday, when the weekly puzzle is released, only a simple key must be downloaded to unlock the weekly puzzle on the cartridge.
It has also been discovered that the cartridge is only holding 162 puzzles. If we subtract the number of puzzles that can be unlocked by playing the single player adventure, 135, and the number of puzzles that have already been downloaded, 6, this leaves us with a total of 21 more puzzles before all of the puzzles on the cartridge have been exhausted. By these calculations, August 17, 2008 will reveal the final weekly puzzle for Professor Layton and the Curious Village.
Readers should be warned that although the linked source is spoiler-free, the link included in that source displays a list of all the puzzles in the game, and their solutions.