Draw in the grid a snake, 45 cells long, not touching itself. Each outlined region must contain exactly 3 cells occupied by the snake. The regions that contain the head and the tail of the snake are marked by grey color.
Answer key: write down the areas of consequtive parts of table, which are not occupied by the snake, in increasing order. For the example the answer would be: 2,3,3,14.
Starting from any cell write in the grid as many digits as possible to create the solvable Sudoku (it doesn't have to have the unique solution). Digits must be written sequentially: 1-2-3-...-8-9-then 1 again and so on. Each next digit can be placed in any of free neighbouring cells.
Answer key: first write down the coordinates of starting cell and then all the moves, according to the table below. For the example the answer would be: A1-U-R-D-UR-D-UR-D-R-U-DR-U-U-L-L-L-L-L-UR-R-U-UR-D-D-UR-R-U. Best answer earns 9 points; each next best answer earns one point less. Additional 2 points bonus is given for the uniqueness of your Sudoku's solution (the example would get this bonus).
Best answer by Alan Murray:
20. A7-U-UR-R-R-R-R-R-DR-U-R-D-D-L-UL-D-UL-D-UL-D-L-U-L-D-UL-D-D-R-R-R -R-R-DR-U-R-D-D-L-UL-D-UL-D-L-U-DL-U-L-D-UL-D-D-R-R-R-R-R-R-D-UR-D-D-L-UL-D-UL-D-L-U-DL-U-L-D-UL-D-UL-U