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This category in other languages:
Abnorm's Conundrums Easy, medium and difficult brain teasers without answers. http://www.angelfire.com/oh/abnorm/
The Amazing Art Site Huge collection of optical illusions, hidden imagery, ambiguous art and upside downs. http://members.lycos.nl/amazingart/
Archimedes' Laboratory Recreational mathematics including puzzles to make and solve, tessellations, geometric puzzles, optical illusions, and curiosities. http://www.archimedes-lab.org
AVAV Collection of optical illusions, brain teasers and riddles. http://www.askix.com/avav/
Bill's Brain Teasers A collection of visual and linguistic riddles. http://www.billsgames.com/brain-teasers/
Brain Juice An assortment of entertaining logic puzzles with solutions and indicated levels of difficulties. http://www.brainj.net/puzzleindex.php
Brain Teaser World Offers riddles, puzzles, optical illusions, and magic tricks. http://www.brainteaser-world.com/
Brain Teasers Brain teasers, riddles, logic puzzles and problems, paradoxes, optical illusions, IQ tests and logical games. http://brainden.com/
BrainBall A daily brain puzzle with 10 different tasks and a variety of statistics on your performance. http://brainball.playwithyourmind.com/
BrainBashers Brain teasers, puzzles, riddles, games and optical illusions. http://www.brainbashers.com/
BrainBoggled.com A collection of math, logic, and word puzzles. http://www.brainboggled.com/
Braingle Includes a huge collection of user submitted and rated brain teasers and riddles. It also has a message board and some unique multi-player games. http://www.braingle.com/
BrainVista Collection of solved and unsolved brain teasers. http://www.brainvista.com
Confusion It's a challenge to reach the end of this puzzle maze. http://cnfsn.tripod.com/
Curiouser.co.uk Paradoxes, puzzles, games, optical illusions, poetry, curious facts, and quotations. http://www.curiouser.co.uk
Eluzions Featuring all sorts of games, optical illusions, puzzles, trivia, mazes, and magic tricks. Suitable for all ages. http://eluzions.com/
A Game A Day A puzzle site featuring a new puzzle format each weekday for each month. Puzzles are fun, educational, entertaining and are also printable. http://www.agameaday.com
The Grey Labyrinth A beautifully illustrated collection of puzzles, riddles, and paradoxes. Features a changing "unsolved puzzle" plus three years worth of previous puzzles. http://www.greylabyrinth.com/
Had To Play On A community based site with competitions, challenges, awards, a help centre, forums and games. http://www.hadtoplayon.com
iRIDDLER Challenge your mind with free online riddles/puzzles, logic games, brain teasers and view optical illusions. http://www.iriddler.com
The Logic Zone Collection of problems with answers, logic puzzles and cryptograms. http://myweb.tiscali.co.uk/thelogiczone/
National Puzzlers' League Crosswords and other word puzzles and games, samples; monthly puzzle magazine; 800,000 word searchable list. http://www.puzzlers.org/
PedagoNet Brainers Over 60 brain teasers to enhance your mind. http://www.pedagonet.com/brain/brainers.html
Planetarium An on-line puzzle story in twelve weekly installments. http://www.beholder.co.uk/planetarium
Professor Tangent Have fun with games, puzzles, brainteasers and humor as you learn about logic and analysis. http://www.professortangent.org
Puzzability Some real mind benders here. http://www.puzzability.com/
Puzzle Contest Center Riddles, brainteasers, cryptograms, anagrams, and logic puzzles. Compete in eight new contests monthly. http://www.contestcen.com/
Puzzles Without Rules Free, updated, original abstract puzzles for advanced puzzle-solvers. Includes current unsolved puzzle and archive with hints and solutions. http://puzzleswithoutrules.blogspot.com/
Pzzls A collection of logic puzzles, riddles and brain teasers. http://www.pzzls.com
Rec.puzzles Archive An archive of many popular puzzles from the rec.puzzles newsgroup. http://rec-puzzles.org/
Roh'El's Riddles Offers brainteasers rated by difficulty and category. http://users.telenet.be/jo.roel/Riddles/index.html
Say What You See! Collection of visual brain teasers which can be solved by saying what you see. http://www.eyetricks.com/swys/swys0101.htm
Thinks.com Recreations for active minds including games, puzzles, math, words, images, books, software and web guide. http://www.thinks.com/
Word Juxtapoz Word puzzles, riddles, rebuses, brain teasers, mazes, cliparts and pictures. http://www.wordjuxtapoz.com/
Zuzzle Puzzles Collection of puzzles including riddles, logic puzzles and sequential puzzles. http://www.zuzzle.com/
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