Puzzles
Braingle.com - http://www.braingle.com/
Find brain teasers, riddles, quizzes, trivia, logic problems and mind puzzles.
Fantastic Contraption - http://fantasticcontraption.com/
An online flash puzzle game where you build whimsical machines to solve each level. Save your contraptions and share them with your friends.
Moms Puzzle Games - http://www.momspuzzlegames.com/
Play free online puzzles, bejeweled, bubble shooters, hidden object and more arcade gameplay.
Puzzle Monster - http://www.puzzlemonster.com/
A free website devoted to bringing you a variety of free online puzzles.