Or a silent, concealed air-powered device for PK effects with non-metals, or shadow-touches in which the spectator feels something but is not being touched.
I write down ONE idea EVERY day in a notebook. The key is to write it down, after time you will have hundreds of ideas and several of them you should be able to make into real working effects. Every trick that I do came from those notes in one way or another.
It is a very simple idea but trust me it works.
Chris