Hmm... strangely I never heard of LEGO (except for the games lol)
I would suggest one of the following two
Python - as simple as it can get, and easy to learn. It has a very simple syntax, all of the blocking being given by the way you indent your code, and it's also made in such a way to be as clear as possible.
C++ on the other hand is not-so-easy to learn, and has a crappy hard to learn syntax... also, you can mess up pretty easy by putting a wrong character where it doesn't belong.
Here's some code to make an idea.
Python code:
http://www.amk.ca/python/simple/letters.html
http://code.activestate.com/recipes/576982/
C++ code
http://www.cplusplus.happycodings.com/Games/code13.html
Of these two, C++ is the most used, and it's also what people learn in schools nowadays, probably because Python is a newer language... but if it were for me, I'd start in python, and that's what I suggest for you too.
Also, if you're interested in games that much, you could try using Blender3D to make 3D games, or pygame for 2d games - those are for python, haven't been looking for what you can do with c++, you could look that yourself.
Blender3d - btw it's a free open source program, based on OpenGL graphics engine
http://www.youtube.com/watch?v=T93HT2SU1pY&feature=PlayList&p=AB6C7CDC3622BEDB&index=1
http://www.youtube.com/watch?v=c7RRaEvWqJc&feature=PlayList&p=AB6C7CDC3622BEDB&index=2
pygame is kinda like flash, except you lack the rich interface, and the movie clips and so, and you code into python, not action script
http://www.pygame.org/news.html