I suddenly had this idea the previous day while walking down the mountain, and had no where to write it down, luckily I remembered it.
I can't remember the exact place I learnt the Bokeh trick, but I think it was here: http://www.diyphotography.net/diy_create_your_own_bokeh
For my cardboard I used an old toothpaste box, locked my bicycle too and olive tree and balanced my camera on a wall while running for 10 seconds (Self timers rock!) to do the Pacman Ghost torch thing. Fun times :)