http://www.spikesgamezone.com/ <- - This is by the same person that does coolmath.... These are the non-mathish games (most are older Java games).

 

http://nlvm.usu.edu/ <- - This is a site with lots of fun math puzzles.

 

http://www.travelpod.com/traveler-iq <- - This is an awesome geography site... Very challenging, even for the best geographers, as you have to pinpoint obscure towns in some levels.... Many different sections, and a fun challlenge!

 

http://www.sheppardsoftware.com/World_Continents.htm <- - This is another fun geography site... Not as hard as the traveler iq site, but still fun! :)

 

http://cube-field.freeonlinegames.com/ <- - This game is very addicting, and quite fun.