Rigging:

Cleanup Check List (english)
Check through this list before you start rigging a character.

Nodes (norwegian)
Explanation of the most important rigging nodes.

Angle Between (norwegian)
How to use measure angles using the angleBetween node.

Point On Surface (norwegian)
Constrain a transform node to a point on a surface using the pointOnSurfaceInfo node.

Character Setup (norwegian)
Advanced character rigging tutorial.

MEL tutorials:

Basic MEL (norwegian)
An introduction to MEL.

Random Light Start (norwegian)
Step by step tutorial with explanation of all the codes in this script.

Dynamics:

Smoke dynamics (norwegian)

Particle Sprite (norwegian)

Miscellaneous:

Rotation (norwegian)
Rotation Manipulators and Gimbal Lock.

Constraints (norwegian)
Two examples on how to use constraints in Maya.