Childrens educational games

Just on the off chance that someone else happens by here, I work with a
fellow who has three boys; ages 5, 7 & 12.

They're having a rather deprived childhood since daddy can't afford an
internet connection - and probably wouldn't, even if he could. Does anyone
have any recommendations for freeware games (*I* can't shell out US$20 - 40
for games for his kids either).

My preference would be for games that educational in nature, but games for
shear entertainment are also acceptable. Anyone have any recommendations
as to games / sites??

//al