[robin2]

Slightly off topic, but Peter Seibel's take on the idea of code reading groups, and the idea of code as literature, is interesting: http://www.gigamonkeys.com/code-reading/

"Code is not literature and we are not readers. Rather, interesting pieces of code are specimens and we are naturalists. So instead of trying to pick out a piece of code and reading it and then discussing it like a bunch of Comp Lit. grad students, I think a better model is for one of us to play the role of a 19th century naturalist returning from a trip to some exotic island to present to the local scientific society a discussion of the crazy beetles they found."

The reason this is off topic is that it sounds like you were after interesting specimens anyway. I don't have any code examples as such, although if algorithms count I'm particularly fond of Tarjan's algorithm for finding strongly connected components in a directed graph, and the Burrows-Wheeler transform (as used in bzip).