Nick's Mathematical Puzzles is just what it says. The puzzles are mostly at pre-college math level, but require a certain ingenuity. Nick provide hints (wherever he can), answers, fully worked solutions, and links to relevant mathematical topics. Some of the puzzles are original, at least in the sense that Nick hasn't seen them anywhere else! His aim is to add at least one new puzzle per week.
curiouser.co.uk is a strange site featuring paradoxes, puzzles, games, illusions, poetry, curious facts, quotations, Rob's Paraboxes, The Runcible Spoon Society and more.
Want to test your math IQ? Find out what it is at iqtest.sk.

Where else can you get PAID TO LEARN?
It Pays To
Learn is a site that pays people and the people they refer to the
program for learning stuff. They have group memberships too, making it
great for schools.
Dancing hampsters??? There is only one word to describe this site: HILARIOUS!!! Plus they have links to other goofball sites.
Her name is Deb. She claims to have a sometimes goofy sense of humour. I'll leave it at that. Check it out at debsfunpages.com.
Shockwave has a lot of games at its site - including some old classics like Centipede. Warning! These games (especially the old ones!) are highly addictive. Just ask yours truly.