Applications of Game theory in computer science? As a computer science student, I have been introduced to game theory, but not seen much detail on the subject. I have searched on Google and looked at some books about game theory and they provided confirmation of its usage in computer science. I have started a formal study of game theory from the economist's perspective. Now I want to know the applications of game theory in computer science. What are some recent major achievements of computer scientists in fields like Artificial Intelligence and Complexity Theory which utilize elements of game theory? Is there a way to approach game theory that is more rooted in computer science than economics?
One of the most famous examples of game theory in computer science is Yao's minimax principle.  Let $X$ be a set of inputs for some problem, and let $A$ be a set of (deterministic) algorithms for that problem.  Yao's principle states that
$$
\max_{x\in X} \operatorname{E}\limits_{a\in A} \left[T(a,x)\right]
\ge
\min_{a\in A} \operatorname{E}\limits_{x\in X} \left[T(a,x)\right] ,
$$
where the expectations on the left and right are taken with respect to any desired probability distribution over algorithms and inputs, respectively.

For example: Any deterministic comparison-based sorting algorithm requires $\Omega(n\log n)$ time on average to sort an array permuted uniformly at random.  (Proof: In any binary tree with $N$ leaves, at least half the leaves have depth at least $(\lg N)/2$. $\square$)  So Yao's principle implies that the worst-case expected running time of any randomized comparison-based sorting algorithm is also $\Omega(n\log n)$.

Yao's minmax principle follow easily from von Neumann's minimax theorem for two-player zero-sum games, where one player provides the input and the other provides the algorithm.