What are some simple tasks for a rube-goldberg machine to do?

a simple one should just have four simple machines and 10 steps.Some can be such as dominoes, pulleys,and inclines planes;also some levers and such. But many in high school levels and some college levels just have thing like this. But you can make it standing up and stuff and one guy in my class made it pinball style.It can knock off a block to lift or flag up and many more technologies