Where can I find source code for ideal world simulation? In many crypto papers I see they use a Real World / Ideal World Paradigm.  However, I have never see the source code of such Simulators that try to simulate the adversary.  Could somebody point me to source code that simulates an adversary in the ideal world? How does this code look like  ? 

An example of a paper that uses this paradigm is on pg. 1244 of this paper.
There is no source code to simulate this. It is a theoretic construct used in security proofs. Cryptography is often about the very limits of what could be calculated. This is quite far from actual programming source code.

For example, quite often something is called "efficient" in cryptography, if the algorithm runs in polynomial time (for some parameter). However, if the source code of a program actually requires $n^{1000}$ seconds then it still runs in polynomial time, but it is not possible to calculate it for $n=2$ (over $10^{293}$ years).

The adversary can not be represented by a specific algorithm, but the adversary is the union of all polynomial time algorithms (or said differently: He is limited to poly-time algorithms, but not specified which algorithms).