The tricky bit would be designing an interface for turkers to manipulate the robot.
The other complicated bit is making sure the turkers can't cause serious harm. (We don't want turkers controlling UAVs...)
If you could craft the game in such a way to provide the control to the robots for things that are not easily automated, people's entertainment would provide the labour required to control the operation for free. A capitalistic dream.
Seems like a Fanuc with a suction gripper and a hires web cam is all it might take to get a little "trashville" going. Give the housewives who collect the most alu while the kids are away at school day passes to local spas as prizes and you've got a win.