I played with Legos all the time...built 1/18 scale cars with working suspension and stuff, lots of fun to zoom my car against my bros to see the damage that could be done...we did body on frame cars, unibody cars, all that, several of which would totally break apart after a slow wreck, while others would break the lego pieces before fallying apart. Built a bus, tow truck, normal cars, a lot of stuff, no instructions just ideas in our heads. It was awsome. Built a motor home with furnature, appliances, a bed, stairs, everything, it broke an axel when I crashed it(it was a light crash, but I hit the front passenger tire and it broke off). Built a huge house, complete with furnature and everything, 2 stories, and just rammed some real 1/18 cars into it...it was awsome looking at the damage and stuff.
Those were the days, we had(and still have) tons and tons of legos.
You can never be too old to play with legos, just you become too lazy to clean up afterwards...