Jolyon Jenkins has produced a Falling Desk Frame that operates by an electronic timing device planted inside the frame (very tiny, by the way). The best part, in my opinion, is that he has included a method for secretly and invisibly starting the timer, something often neglected in past electronic wonders ( you had to yank on a switch before the timer would start). With his method, you don't start the timer until you are ready and then it can simply be done with a "mystic pass" or lighting a candle, or some other innocuous act. It's on my site, number 3 in the Magi-tronic section. Not for beginners unless you have some background in putting together electronic projects. If you don't have a need for a desk frame that suddenly topples over (and which can be immediately reset to do it again whenever you desire), you may still find the circuit and diagrams helpful for any other electronic device or mechanism that could be improved with a timing circuit and a way to start it invisibly.