The first one I'd seen was implemented in a Ruby book, and I agree it's a good yet moderately challenging problem to do. Once you're done solving the base case, making improvements like implementing a more efficient backtracking algorithm or drawing a board within a GUI can be added as well.

Edit: The book was 'The Ruby Programming Language' by O'Reilly Publishing, not 'Programming Python' as I originally thought, also published by O'Reilly.