http://www.nsa.gov/programs/kids/standard/index.shtml
Surreal web site maintained by the NSA as part of the the NSA for Children's site, it consists of a spooky, decaying Virginia mansion with lots of Flash-enabled puzzles. Wish I could do more with it; it keeps on crashing my browser. (Dammit!) The name is a play on "Puzzle Palace", a standard nickname for the No Such Agency's headquarters.
It makes me think someone, somewhere, is rolling in their grave...