GuerrillaCG Modeling Series
Guerrilla CG : The Polygon
The Polygon from The Guerrilla CG Project on Vimeo.

From Guerrilla CG:

The polygon is the basic building block of all 3d models. Here we discover its properties, like the face normal, which shows the direction the polygon is facing and it's three components the face, edge and vertex. Complicated objects are made of lots of polygons put together. (2:26)

*Edit, the terms "Planar" and "Non Planar" should be "Coplanar" and "Non Coplanar" respectively.
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.