I wrote two little python extensions for Inkscape to create grids for crossword and sudoku.
At the moment crossword allows to create free schema crosswords, no schema crosswords, syllabic crosswords. It can also choose randomly which cells must be black if the user does not specify his preferences. The user can also specify help letters that will be inserted into the grid. You can find it here
The sudoku extension supports: - Sudoku - Mini Sudoku - Sudoku X - Hyper Sudoku - Sudoku Samurai. You can find it here.
On the italian forum these extensions received positive feedbacks; thanks to the users' advices the plugin are now much better than the first draft.
Their source code is still ugly and messy, I'll clean it as soon as possible, however at the moment they work quite well (I think). They are released under GPL v3. I hope you'll like them and I hope this is the right section to post about them. Feel free to suggest me improvements!

Best regards,
Fabio