WU Forums
ocf.berkeley.edu
Discussion board hosted at Berkeley with talk about a variety of solved and unsolved brain teasers.
IBM Research: Ponder This
researchweb.watson.ibm.com
Monthly logic and math puzzles set by IBM researchers with solutions.
Jim Loy's Puzzle Page
jimloy.com
Classic and original puzzles.
The Truth Tree's Math and Logic Board
truthtree.com
Collection of math and logic puzzles ranging in levels of difficulty.
TechInterview
techinterview.org
Answers to technical interview questions, programming problems, and brain teasers.
Leisure Ideas: Puzzles
leisureideas.com
Some mathematical puzzles with answers and/or a hint.
CellFighter
cellfighter.com
Shareware game based around an extension of the game of life.
Perplexus
perplexus.info
A forum and collection of brain teasers, logic problems, math problems, paradoxes, science games, probability, riddles, and geometric shapes. The puzzles are searchable and categorized, most have solutions.
Two Envelope Paradox - Solution
anc.ed.ac.uk
Claims that the two envelope paradox comes from the incorrect use of probabilities.
Mathematical Jigsaw Puzzles
home.hetnet.nl
Information on polyominos and square puzzles.
Monty Hall Game
montyhallgame.shawnolson.net
JavaScript example of the Monty Hall Game. This game demonstrates the real (empirical) affect of statistics. [Does not display correctly in all browsers.]
The Monty Hall Problem
remote.org
A probability theory puzzle with solutions. [English and German.]
Quick Logic Puzzles
robertwilliams.org
Use the clues provided to deduce the correct sequence of numbers in the hidden code.
Kakuro-san
kakurosan.com
Providing graded Kakuro puzzles every day, plus old puzzles.
The Puzzles of Oscar
uk.geocities.com
Contains puzzles and games with solutions.