Cool Online Puzzles

As fond as I may be of online quizzes I enjoy online puzzles even more so if you too really need to challenge yourself a little (or a lot) than I recommend working on a really challenging puzzles.

After some very hard work you might be ready to start another one.

You might want to check the Puzzle weblog as the recent posts there linked to some cool puzzles which are very hard to solve and those are always the best ones.