Mike Downes posted a neat Google search trick on Google+ where you can search by voice on Google Desktop without having to click the microphone icon with your mouse. Instead, you press control (on Mac, command), shift and period. It will then jump you directly into voice search.
It is that quick. Now if your mouse stops working and you get tired of typing more than three key presses, you can just type control + shift + period to put yourself into voice search mode on Google.com.
Give it a try yourself!
Forum discussion at Google+.