Picture matching card games, jigsaws, and more.
www.gotofreegames.com
Math Games galore involving probability, illusions, fractals (if you play you'll find out what they are).
www.cut-the-knot.org
Traditional board games to animated cartooons. Some require good hand-eye coordination or may be hard to see, but sound effects and lively graphics make them fun.
www.puzzledepot.com
Offers excellent brain stimulators from syndicated columnist Terry Stickels.
www.terrystickels.com