Building

LDraw.org - LDraw™ is an open standard for LEGO®CAD programs that allow the user to create virtual LEGO models and scenes. LDraw is and always will be offered free of charge.

brickplayer.com - Private, independent website featuring LEGO sculptures, mosaics, news, reviews, and building tips & tricks.

brickjournal.com - BrickJournal is a magazine that spotlights the many aspects of the LEGO Community. Events, people, and models are showcased in every issue, with a couple of surprises too! BrickJournal journalist Joe Meno is always found at the FLL® World Festival.

brickshelf.com - Cool LEGO building stuff.

peeron.com - More cool LEGO stuff, including a list of parts numbers and names; color chart, sets, building instructions (often old item no longer available on www.LEGO.com).

classic-castle.com - For LEGO castle aficionados.

bricklink.com - Premium venue for individuals and businesses from all around the world to buy and sell new, used and vintage LEGO® through fixed price and auction services.

brothers-brick.com - The Brothers Brick is a LEGO blog for adult fans of LEGO.

lugnet.com - International LEGO Users Group Network, a global community of LEGO enthusiasts. LUGNET unites LEGO fans worldwide through forums, web pages, and services.

The Art of LEGO Design by Fred Martin- A slightly outdated, but still very useful guide to building with LEGO. This document covers building robots that don't fall apart.

Simple Machines

EdHeads - Learn about simple machines as you explore this house.

Chicago Science Museum - Help Twitch create simple machines to trade distance for force.

Fantastic Contraption- A fun physics puzzle game.

Power Play- An activity about capturing power with simple machines.

Curriculum

Trifolioum Gears Lesson
A lesson plan about gear types and uses using LEGO gears to illustrate. Introduction to gears lesson.

How Stuff Works
This is a great site for explanations of how things work. It is not a curricula, and not specific to FIRST LEGO League, but has very good explanations of general engineering concepts. For example, How Gears Work, How Gear Ratios Work, and How Differentials Work.
 

Education Standards

This document maps FIRST programs to the Common Core Math Standards, National Science Standards and 21st Century Skills Framework. (US specific)