I used this around the deck this year.
http://www.havahart.com/ourbrands/critter-ridder
I used the spray type under the hood of my wife's Rav4 which was getting filled with acorns everyday. (Well inside the hood anyway.) And have not seen any chipmunks at all this year, since using it. Must work....
Oh and it does not smell too bad either, like some of those products tend to.