I've collected a handful of useful tutorials that involve keying or rotoscoping to isolate talent or objects. You never know where you might end up when you start removing your background. :)
Posts in this series

5 Basic Ways To Populate Mass Groups Within After Effects

Extending Your Set With Cinema 4D

Double Stuffed Tracking Walkthrough

Leap Into Hancock-Style Super Jump Effect

Elemental Combat Series: Flamethrower

Elemental Combat Series: Electric Hands

Elemental Combat Series: Flaming Arm

Simple Principles To Make Rotoscoping Less Crappy

Enhanced Night Vision Goggles

2D To 3D Stereo Conversion With Mocha Pro & FreeForm Pro

Matchmove A Bloody Severed Leg

Rotoscoping Depth Mattes With CameraTracker

Basic Footage Coloring And Object Removal