Professor Layton and the Lost Future.
I adore those games. Absolutely adore them. They're so easy to pick up but immensely frustrating because some of the puzzles are so effing hard xD ARRGH!
Also just completed Samurai Warriors: Chronicles for the 3DS. Huge fun but ultimately a little bit of a non-event because once you've completed the story mode and the Gaiden levels, there's nothing else to do but play it through again on a different difficulty with a new character. Fail, Koei. Fail. They should have just imported the FULL Samurai Warriors version to the 3DS. It could handle it easily.
