As a complete novice, I have been doing some research to find a fairly simple GBC module to build. I found plans for a Classic Marble Pump on Planet-GBC, then went rummaging in my parts drawers to see if I had enough bits to put it together. This is what I came up with!

The plans built me the input side, which I dubbed Big Bird. Then of course I had to add some wings and eyes! It is built from mainly System bricks apart from some gearing and the motor hidden behind. I didn’t have enough of the same coloured bricks to build it out of one colour, but who cares – multicoloured is more fun!
Then I had to get the balls back down again to the right height for the next module’s input. I decided on a pinball type board, built from Technic beams, with pins stuck in them in a triangular pattern, built to my own design. I think it works quite well. Tomorrow we are taking it to Caterham for a test run with other GBC modules made by the London AFOLs.