Concerning the previous Sudoku post: The best online implementation is probably here. It's written in Flash, you can easily copy it to your hard drive.
The best FREE implementation for Palm PDA is here (although the random puzzle generator currently sucks). There are other (non-free) implementations.
And no, really, I've never before heard about Sudoku (also called "Number Place"). I don't read printed newspapers.
UPDATE: The Flash page linked above generates puzzles (on "Hard" setting) with more than one solution! I guess these are not valid Sudoku puzzles...
UPDATE 2: "Anonymous" wrote that "official Sudoku puzzles" actually have to be symmetrical (which is NOT true for most of the puzzles I found on the web). See Wikipedia entry.