FitTris may be the most addictive solitaire game since Free Cell or Tetris itself. The goal of each puzzle is to fit Tetris-like pieces into a square grid leaving no empty spaces at all. Puzzles get more difficult as grid and piece sizes increase. Once you have mastered the basic version, you can try the Spaced-Out version where all the individual pieces are physically disconnected but still move as one. The seamless interface allows both a dragging and dropping to work as well as a click to pick-up and click to place pieces. With 6 distinct puzzle variations and 5 difficulty levels, there is plenty to keep everyone happy from novice to expert puzzle solvers.