The Kindle besides being a most excellent reading device (here is a handy review of the thing) is also the perfect handheld for enjoying text adventures. Then again, it also seems pretty capable of handling a variety of other, mostly word and puzzle, games. Number Slide is a pretty perfect example of the sort of stuff currently available for Amazon's handheld. It's a number-sliding puzzle game with simple graphics that can be grabbed here. Oh, and it's happily freeware too.