This site features a couple science-related Lego gift ideas AND several very cool educational science project ideas!
Also on these boards
DIY Portable LEGO Kit with Free Printable Activity Cards. A great idea for those times where you have to wait (Doctor's office, restaurant) or when you are traveling (great in the car or on a plane)! From Fun at Home with Kids
DIY Removable Non-Permanent Lego Wall from Lalymom. Great for any Duplo or Lego Lover.