I've been giving a robot belly rubs. I've scolded it for being a bad, bad boy. I've grinned when it greets me at the door. And I felt it for Aibo, a new "autonomous companion" dog made by Sony. Does that make me a sad sack?

Last year, the Institute of Robotics and Mechatronics at the German Aerospace Center created the "Rollin' Justin" robot, a technical marvel that could catch a ball through a mix of precision, user input, and motion sensors. It proved to be a success, but there's only so much research you can do with a single-function robot. Enter "Agile Justin," the counterpart machine that can pitch a ball with a great deal of finesse. Huffington Post relayed video footage of the two robots in action, as each unit showed off their respective skills in a short game of catch. It's a neat thing to watch in terms of mechanical detail, especially when you consider that each robot has to mimic the hand-to-eye coordination required for a seemingly simple thing.