Algorithms & Complexity Theory

Algorithms

Basic Data Structures & Algorithms - Including: Linux Kernel, Google Chrome, Core *nix utilities, etc...
Problem Solving with Algorithms and Data Structures - An interactive, online ebook on data structures, algorithms, and analysis.
Data Structures and Algorithms in Java - Comprehensive collection of algorithms implemented in Java.

Turing Machines

MOV is Turing-complete - Using just this instruction, they demonstrate how an arbitrary Turing machine can be simulated.