At first Lego sued their own customers for hacking Mindstorms software and then embraced them, mainstreaming the "hacked” code by allowing users to share what they had created in a Mindstorms forum.

Lego also crowdsources its concept development and testing by sponsoring the online Lego Factory. Here anyone can design virtual Lego scenes, customizing blocks and colors. Rules built into the system prevent customers from building scenes that cannot be reproduced in the physical world. Lego product people now have a lab running 24/7 where they can observe customers developing and purchasing products.

Links:

Lego Factory
Lego Mindstorms