Even hiring some people to bury dollars, and hiring others to dig them out would stimulate the economy.
The problem with such a purely Keynesian approach is that, when the holes are filled in, the digger is again out of work, and the country benefits not one bit from the hole.
A much better approach to stimulus (if one believes that it is necessary) is to fund projects that not only put people to work, but also provides a benefit once completed - the best case being that the benefit is economic in nature.
At the risk of being accused of having an agenda, I'll use building nuclear power plants as an example. If this effort were undertaken as a stimulus project, it would put people to work, build an infrastructure that continues to supply jobs even after the project is complete, lower energy costs, and reduce dependence on fossil fuels.
"Stimulus" projects that provide no lasting economic benefit once completed are rightly called "pork".