Rigging Tutorials 2.5x

Creating an FK/IK Arm by revolt_randy Covers: Creating a rotation constraint-based IK/FK switch and driver
Rigging Dog Legs by Sebastian Konig Covers: Quadruped Leg Rigging
Muscle Deformations by Eibriel Covers: Brief explanation of using shrinkwrap to create muscle flexing.
Rigging Introduction by tleave2000 and Foot Rigging Part: 1, 2, 3, 4, 5 Covers: Rigging a reverse foot
Leg IK/FK Switch by tleave2000 Part: 1, 2 Covers: Creating a 3 chain IK/FK switch
Spline IK Octopus Setup by Gimble Covers: How to make the octopus Spline IK example
Rigging the Face, Fingers, and Spine by Dimitrii Covers: finger, spine, and face rigging
Rigging a Crankshaft & Piston by revolt_randy Covers: rigging a simple crankshaft from start to finish
Lesson 1: Objects and Components by Gord Goodwin Covers: Overview of rigging elements and their behaviours
Introduction to Rigging by Mr. Deyo Covers: Introduction to rigging and basic character setup
Simple Rig Solutions by Mr. Deyo Covers: How and why to use Auto-IK on a rig