LINQ

http://davidhayden.com/blog/dave/archive/2007/01/29/LINQVideoAndersHejlsbergLINQTutorials.aspx

.NET Expression Tree

This blog has been great for understanding expression tree, a cool feature
since C# 3.0: http://www.davidhayden.com/blog/dave/archive/2006/12/18/ExpressionTrees.aspx

The MSDN one seems a big vague:
http://msdn.microsoft.com/en-us/library/bb397951.aspx

A review of "Python In a Nutshell" by Alex Martelli; O'Reilly Media

Python in a Nutshell provides a comprehensive introduction
and coverage of Python. For people with basic object oriented
programming background, the book can quickly gives a good
overview and coverage of the most fundamental core concepts
of Python. Then the book goes on to discuss different aspects
of Python. The advantage of this approach is that you could
quickly get an overview of Python, and could selectively
read the remaining chapters or as references at hand.

I particular like the indepth discussions of Chapter 5
Object-oriented Python where different aspects of Python
OOP from other OOP programming languages are well
explained, and greatly helped me.

O'Reilly Media - Bookstore

Artificial Intelligence Site

An intelligence search engine called
TrueKnowledge, unlike Google, provides
precise answers to questions. Essentially,
the search engine builds a large database
consists of objects and facts linking these
objects for inferring answers for user
questions.

http://www.trueknowledge.com/