Building Lego Robots is amazing. Here are some great tutorials that get you through the tricky parts of making the bricks sentient. Note: not sure if tutorials are actually operational?
The following lesson plans are for free use by Teachers of Robotics using the LEGO NXT Mindstorms Education kit.
There are Junior, Middle and Senior School Lesson Sequences and plans that build on Robot Educator.
They are designed to be used in an approximate 6 week block, but feel free to access single lessons.