ideas for project :)

hey group!
I had a couple of ideas for the project, as I was telling the group last night we could incorperate the lighter leash into our project, it is a retractable device with a clamp on it, it might be useful if we had someting holding whatever we put in it(it doesn't have to be a lighter) and then when it lets go it will retract and this could cause a reaction.
I was also thinking that we could incorperate the people we learn about in our class and their laws for example, Newtons Law F=MA (If something falls to cause the reaction w=mg).
Also we could use the steps of our machine to display some of the common concepts of mechanics like magnets,pulleys, springs,tension,torque,etc... and include this stuff in our final write up to give it some depth.
I think the final goal of the machine should be something that will easily be set off so that the machine will work everytime.....what about a machine that adds cream and sugar to your coffee? :)