Before I got on the computer, Legos, Barbies, videogames and drawing were my four main hobbies. With Legos, there was no limit on creativity... okay there was since I only had enough blocks to build a modest house and seal it and I didn't have that many colors (red, blue, yellow, black and white with some odd colored blocks now and then) but hey. I was a creative kid.
Now Legos just can't satisfy my creative needs. If I build something 3d, I use Google Sketchup or the Sims 2 on building mode.
I can never forget this one giant Lego palace. It wasn't anything special other than its mass. It was merely composed of blocks and maybe windows but it was large and it looked deep and all my childhood I wanted to make a Lego palace like that. I can compare it's mass to my local hospital which is a giant mass that you can get lost in.