I woke up to the kids & their continuation of lego fun from last night.  I wondered what the possible universal, timeless, psychological draw was to these little building blocks.  And, I wonder why the directions aren't in 3-d yet?

Curtis Silver had a solid answer for the first question:

http://www.wired.com/geekdad/2009/06/lego-love-affair-a-geekological-profile/