nerdyWell, I've gotten my first version of the RetrievalBot complete. It's a track-chassis Roverbot (one of the basics in the Lego Mindstorms Constructopedia) with a single bumper on the back, and a homebrew odd spring-ish arm.
Pics: (all images are 800x600, hence just links)
http://www.weyr.org/~kistaro/SideView.jpg
Side view of the robot.
http://www.weyr.org/~kistaro/SideViewArmUp.jpg
Side view, with the retrieval arm fully up. It can continue another 90 degrees forward to pin an object. (Hand, shirt, and pants belong to my father.)
http://www.weyr.org/~kistaro/TopView.jpg
Top view of the robot.
http://www.weyr.org/~kistaro/FrontViewArmDown.jpg
A front view of the robot.
http://www.weyr.org/~kistaro/FrontViewArmUp.jpg
Last pic: front view of the robot, arm up. The hand in the image supporting the arm is mine.
And yes, the robot's arm is able to move on its own; it just hasn't been programmed yet, hence is off, and therefore is not powering the motor.
I have to say, that's quite possibly the most complicated way of doing it I can imagine. I use the pentactyl attachments to the ends of my forelimbs, commonly known as 'hands' ;)
And hands just aren't as much fun. But if you want "complicated," get a Rube Goldberg machine.