My online gaming world just got much more interesting.
And much more geeky.
I've learned about The Hardest Logic Puzzle Ever. Awesome.
And, in the same vein (but less superlative), here's a site full of Knights and Knaves puzzles (Knights can only tell the truth, Knaves can only lie, and you can only ask yes-no questions. Can you tell which is which?)
Here's another logic puzzle site I frequent. It doesn't have story-based puzzles, but it does have plenty of sudokus and other interesting grid-based logic puzzles.
(Thanks to commenter Berenike for pointing me to Agent Intellect, who links to the above games here. Agent Intellect's blog is intriguing in its own right too.)