There are some nice puzzles there. There is some overlap between my favourite puzzle page, by Rustan Leino: http://research.microsoft.com/en-us/um/people/leino/puzzles...., but both have a number of puzzles the other doesn't.

Edit: corrected Leino's name.

This is a nice list, thanks for sharing. Here is another which many of you probably know but isn't linked at the bottom of the article: http://paulbourke.net/fun/

I do wish the comments were hidden by default.

Do they have to be laying on a surface?

I worked briefly on the same team as Gurmeet while I was an intern at Google. He's an incredibly smart guy and had tons of interesting puzzles to give out.

Great list. Many of you may also like: http://mindcipher.com

More puzzles: http://www.folj.com/puzzles/

the graphical soln to 40 is beautiful.