Might as well start with the simple stuff first; was it in neutral/have the clutch in?

 

First thought is dead battery, but if that is good then I would begin to think starter. My 05 did that intermittently, and until I could have it replaced under warranty, rapping on the starter with the butt end of a screwdriver while hitting the start button usually did the trick. Turned out to be something bad in the solenoid, and it wasn't allowing it to fully engage.

 

If it is clicking also check the battery cable especially the negative cable. If it is even a little lose it can do that.