My original favorite engineering "game" was Garrys mod, which is basically just a playground using the Half Life 2 physics and game engine. I had great fun slapping wheels on something like a bathtub and making a makeshift car, or making silly Rube Goldberg style machines using levers, ropes, thrusters, etc. Not a typical game since it didn't offer any typical goals or levels outside of have fun and be creative, but that IMO only heightened the inspiration to engineer stuff to play with.