You would roll metal ball bearings down a plastic chute and at the bottom the ball would bounce off a small, strategically-placed drum (kind of like a miniture trampoline), which propeled the ball to the next drum, and then to the next one and so on. It came with 3 or 4 drums. The idea was to place the drums so that the balls would keep bouncing all the way to the last drum (maybe the last drum was really a cup to catch the ball, but I don't remember).
Regarding the above toy - in the UK I remember this but it was a bit different (I don't even know what it was called). You had a mat with 3 (or 4 ?) circles on where you placed the 'drums' (I remember you had to assemble them yourself, using the ring frame and then stretching a plastic skin over them). You then had a chute that ran down one side of the mat, which connected a 'collection tray' to the 'feeder tower'. The collection tray was just that, a tray that caught the ball bearings when they bounced of the last drum. They then ran down the chute to the feeder tower which was a clear plastic tube with a screw inside - this screw was turning and fed the ball bearings to the top of the tower, where they were released from a small chute at the top to start the process of the balls bouncing from one drum to the next in a satisfying cascading arc. I remember this toy quite vividly, as that was all that you would do - watch ball bearings cascade from one drum to another, and then be fed back to the beginning again ! You can see a rough diagram (drawn from memory) at; http://tinyurl.com/aan8/ablufia/FOLDER%20pictures/bing_bang_boing.gif Cheers ! Ablufia