Puzzle

Bradley University's Math Problem of the Week     -  "On Monday of each week (at about 3:00pm) during the semester I'll pose a problem for you to think about. Solutions for the problem are due at 3:00 on Monday of the following week. For my enjoyment, please be sure to include with your submission an explanation of how you arrived at your solution. The Bradley student(s) submitting the best solution will be awarded a $1.00 weekly grand prize! Of course, everyone can play, but only Bradley students are eligible for the huge cash award (...the rewards of paying tuition)!"
Car Talk: This Week's Puzzler     -  "Every week on our NPR radio show, Car Talk, we present our listeners with a curious little conundrum. Sometimes it actually has to do with the inner workings of cars. But more often than we'd like to admit, the Puzzler has to do with more esoteric things like the bubonic plague, electric trolleys in Brooklyn, or the urgent need for a haircut."
Flooble.com     -  "Welcome to flooble :: perplexus, flooble's perplexing puzzle portal. Here, we collect all sorts of puzzles, from simple logic questions and word tricks to in-depth math problems like probability and geometry. Click around and see if your brain is up to the task!"
(Math) Problem of the Week     -  A Math Forum Project. Includes weekly problems in each of algebra, pre-algebra, geometry, math fundamentals, pre-calulus. Also posts problems in elementary, middle-school, trignometry, calculus and discrete math.
Portal to Problems of the Week     -  A comprehensive listing of problems-of-the-week Web sites. Divided into Elementary, Middle Grades, High School and Advanced
Puzzle of the Day for Kids     -  by BillyBear4Kids.com
Word Game of the Day     -  Meriam Webster's word game of the day. "Play a Classic Word Game every day or visit our archive to play games you missed during the past two months. Our Classic Word Games come in four fun formats"