I mounted my iPhone on my Bicycle. I am using RunKeeper to track my cycling route and this way I can pick up a few extra seconds.
I have been loosing time by stuffing my iPhone back into my pocket after I start and then pulling it out just before I cross the end of my route. Every second counts when you are going for a personal best. I think I should be able to knock off 4 or 5 seconds from my time with this simple change.