Macalester College Problem of the Week - Weekly math problem and archive from Professor Stan Wagon for first-year college students presented by the Math Forum. Monthly Problem - Math problems and solutions from Math Central. Ken Duisenberg's Puzzle of the Week - Problem archive and puzzle links. Math Magic - Devoted to original mathematical recreations with puzzles and links. Math Forum: Geometry Problem of the Week - Past archive and solutions. Receive help from mentor. Paid membership required to view problems. Math Forum: Algebra Problem of the Week - Past archive and solutions. Receive help from a mentor. Paid membership required to view problems. Problem of the Month - Posted by the Mathematics Department of Bilkent University. Purdue University Problem of the Week - Weekly math challenge with past problem archives and solutions. Math Forum: Discrete Math Problems of the Week - Past problems and solutions, student recognition. Paid membership required to view problems. Math Forum: Math Fundamentals Problem of the Week - A weekly interactive project for elementary school mathematics. Past problems, solutions, and student recognition. Paid membership required to view problems. Math Forum: Problems of the Week - Projects from the Math Forum presenting weekly interactive math challenges to accumulate points for bronze, silver and gold prizes. Individual or class participation. Paid membership required to view problems. Problem of the Fortnight - Twice-monthly problems with archive and solutions. IBM Research Ponder This - A monthly on-line competition hosted by researchers at IBM.