Here is a list of game engines and tools STEM educators can use to create lesson plans and curriculum for video game based education:

Game Design Tools

This is a master resource list used by Global Game Jam participants.  Some of these resources are free and low cost. Most of these are good for middle- high school age and above. I highly recommend Game Maker and or Game Salad game engines since they have a huge community online and there are many tutorials available. You can even publish to the web, and/or test a iPhone or android device.

Basic Game Design Principles

For those on the younger end, Game Star Mechanic is a free website and online ciriculum that teaches game design theory and systems thinking.

Video Game Ed Curriculum

Their parent company E-Line Media makes educational games and curriculum for educators. Please check them out as well.

You may also want to join the Institute of Play for teacher support and training using video game curriculum's-