Entertainment, Games, Puzzles, Brain Teasers, Optical Illusions - Mindfake.com. Site contains a collection of optical illusions, online games, and other fun things.
Nonstop fun with the world's best logic puzzles: Sudoku and Sudoku variants, Pic-a-Pix, Link-a-Pix and other logic puzzles updated weekly. Play online and print on paper.
Entertainment, Games, Puzzles, Brain Teasers, Nonograms - Elite Japan Crossword. Downloadable software for solving paint by numbers puzzles in many formats, including plain black and white bitmap files.
Entertainment, Games, Puzzles, Brain Teasers, Mathematical - Perplexus. A forum and collection of brain teasers, logic problems, math problems, paradoxes, science games, probability, riddles, and geometric shapes.
Entertainment, Games, Puzzles, Brain Teasers, Cryptograms - Between Waters. Daily problems and solutions available with or without interactive browser-based solver.