For those of you who don’t know the game of Fifteen Puzzle, according to Wikipedia, it’s a “sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing.<...> The object of the puzzle is to place the tiles in order (see diagram) by making sliding moves that use the empty space”. (Wikipedia)

Fifteen Puzzle is available for WVGA Windows Phones (already tested on the HTC HD2) and you are presented with a screen of randomized numbered blocks which you need to reorganize in their order from 1 to 15 with the number of moves and time it takes being counted.

(Source: XDA Developers)