Cluefinder Adventures - There are many levels, most have been greatly enjoyed
Road Adventures by The Learning Company
Math for the Real World
The Logical Journey of the Zoombinis and other Zoombinis games
Magimixer, 24 game, Ceasar and Cleopatra (takes longer to play), Traffic Jam
Civilization (I, II & III), Master of Orion II, and Rise of Nations.
Dr. Brain series, The Incredible Machine series and Sim City.