Ages ago, I started coding up a perl-based sudoku solver and managed to get it solving lots of puzzles with only a very basic set of rules for solving them. Recently, 
alnitak (who is also writing a solver, this time in java) showed me a really nasty puzzle which neither of our solvers could completed (although a human could spot the next step). After some discussions we came up with a new solving rule, which I've implemented in my code and now allows me to solve the puzzle.
Anyway, what I'm looking for is some truly evil sudokus to test my solver with, so if you've got any nasty ones that you can send me, that would be much appreciated.
+---+---+---+ |738|.1.|.9.| |.9.|5..|74.| |..4|...|...| +---+---+---+ |64.|28.|3..| |...|...|...| |..2|.95|.87| +---+---+---+ |...|...|1..| |.87|..2|.3.| |.5.|.6.|279| +---+---+---+
