SET game http://2n1.org/applets/set/
Brainteasers for Kids http://kids.niehs.nih.gov/braint.htm
Plexors of the Month http://www.huensd.k12.ca.us/GATE_01/gate/plexers.htm
Analogy Game for Two http://www.quia.com/cb/7146.html
Gamequarium http://www.gamequarium.com/index2.htm
A Game for the Geography Whiz in you! http://www.eduplace.com/geonet/