This post is about quadrotors:
AeroQuad is an open source quadrotor project.
Here is a video of A Swarm of Nano Quadrotors, and Aggressive Maneuvers for Autonomous Quadrotor Flight.
Here is a video of a MK Mikrokopter looping.
Here is a list of Quadrotor, Kits and Parts, Drones For All Tastes and Budgets.
Draganfly offers the Draganfly X4.
AscTec makes the Hummingbird.
Quadrotor shopping list