my kids love scribblenauts.
really, it will depend on what you consider educational. My oldest ds has age of mythology on both the computer (my old game) and the DS. It is highly educational because he's learned just about everything about mythology and a ton of military strategy, soldier types, etc..
Video games can be highly educational, even when they don't look like it because they require children to think logically and to do a lot of problem solving. For example, in the
lego games (star wars, batman, iniana jones etc) the kids have to figure out what they have to do to clear each level. Many of these are small puzzle problems or a set of logical steps that must be taken in order (pull this here, push that there etc to open the next thing). Not educational in the sense that your learning facts nad figures, but it IS educational in that it is wiring my kids brains for problem solvingand logic. I know the regular indiana jones game we have also has similiar puzzle type things you have to solve.
We also have one of the mystery games where you have to find the objects hidden in the room which can be pretty tough (again not facts and figures educational but more brain wiring)