LOGO the programming language had a cute interface with LEGOs. Through LOGO programs, you could steer cars in a LEGO city, control traffic lights and do just about anything your imagination could come up with. I expect the systems were pretty expensive as I never had any friends who owned this, only schools.

Now LEGOs has a similar something called MindStormsTM, which I haven't scraped up the cash to get, but will someday.