GuerrillaCG Modeling Series
Guerrilla CG : Multisided Polygons
Multisided and Intersecting Polygons from The Guerrilla CG Project on Vimeo.

From Guerrilla CG:

In this tutorial we look at how polygons can have more than three sides. We discover quads and n-gons and see how these multisided polygons are still made of hidden triangles. We explore how quads are useful for subdivision smoothing and how triangles are good for games models. And in the second part of the tutorial we look at intersecting polygons, and how they are useful in certain circumstances. (3:56)
GuerrillaCG Modeling Series (Beginner)
GuerrillaCG : The Polygon
GuerrillaCG explains the polygon: the basic building block of all 3d models.
GuerrillaCG : Multisided Polygons
GuerrillaCG explains multisided and intersecting polygons.

GuerrillaCG : Objects
GuerrillaCG explains objects and why they are useful.
GuerrillaCG : Primitives
GuerrillaCG explains primitives, and how to use these convenient starting points.

GuerrillaCG : Subdivision Artifacts
GuerrillaCG explains the relationship between topology and smoothing.