All the Maxis Sim games will teach you lots while "gaming". Theme Park as well. I'd venture to guess that any text adventure teaches you plenty (grammar, sentence structure, improves memory, stimulates imagination, etc.) and wish they were more popular with kids these days since their writing skills, speech and grammar are in the shit today.
Umm... also, gotta give props to the Edutainment titles out there for smaller children. Katies Farm and that sort of thing. Just gave away 5 titles for the Amiga in fact, to a buddy nearby that plans on having kids someday and is a big Commodore & Amiga fan
