Here you will find a range of Sudoku problems (with solutions) of varying difficulty.
A few years back I created a few problems each week and placed in a blog. These included exotic geometries in addition to the regular 9X9. In fact I usually avoid the normal 9X9 since it is available in all newspapers and I believe that some of the irregular shapes pose a different kind of challenge.
Due to other pressures I stopped posting these problems at end 2015 but they are all available here with solutions, grouped by month.