(I don't know about the other sides of the two ponds, but here between them we call running around and collecting all the practice balls that we have hit/thrown/launched/kicked in practice "shagging", so there's that)
Balls with little RF transponders in them. Robotic autoshagger equipped with an RF interrogator.
Autoshagger has all the technology to find the signals, pick one of them (perhaps the strongest one - in our application, the return signal will be fairly weak, as balls provide little room for the transponders and antennae, so the strongest signal can be assumed to be the closest?), and home in on the ball. He also has close-range optical and robotic arm technology to pick up the ball and put it in his sack.
When his bag is full, or he gets no reply signals, he brings the balls back to you.
Now you can get your reps in, even if everyone else on the team hates you and you are a very lonely athlete.-- globaltourniquet, Jul 26 2007 I'm pretty sure the actual state of art in robotics would allow the robot to pick up the balls by sight. No radio needed.-- Flima, Jul 26 2007 I'm so glad that this is not a super hero duo. In fact, glad enough to give you this. (+)-- 2 fries shy of a happy meal, Jul 26 2007 A full optical sensor implementation has the distinct advantage of being able to use regular balls, but the advantage of the RF implementation is that the robot (a) would not accidentally pick up a thing that it is not suppose to, such as a ball-shaped severed head lying on the practice field, or (b) would not have to have extremely complex optical sensing technology to differentiate between balls and severed heads. Not to mention differentiating between your balls and the balls belonging to the poor sap who has to shag himself.-- globaltourniquet, Jul 26 2007 [2 fries] Excellent-- hippo, Jul 26 2007 Like a Roomba, but better! [+]-- Noexit, Jul 27 2007 random, halfbakery