Not my blog, but this is where I learned game theory.

http://letuskode.blogspot.com/2014/08/grundy-numbers.html

I can really recommend Game Theory by Thomas S. Ferguson. The first few chapters are the important ones. It might be 25 pages, but it is really well-written. You completely understand the ideas behind game theory. Also, there are a huge number of examples. Once you get the ideas, you can skip a few of the less important ones.

!(You can learn by playing game) :)

https://codeforcex.quora.com/Game-Theory-with-examples

Is "Winning ways of your mathematical plays" a good book to learn game theory? (I don't even know if its for beginners or advanced)

Commenting because I thought it's a relevant question to ask here.