Use the Force. Avoid the sprinklers.

It was not the first time they had confronted each other. They had fought before on Tatooine, many years ago, before one tracked the other to this tiny planet, to this tinier suburban complex. One had stayed true to the Force, had followed the teachings of his master and had served the forces of good. The other had forsaken the light, turning to the dark side, seeking power above all else. Why this quest had brought him here is a mystery, unless he wished to have power over the local bicycle population.

They ran into each other on the hot asphalt of the road, drawing their lightsabers. The local boys noted what was about to go on, and moved the hockey goal they had set up in the street until the fight had passed. The air was soon thick with ozone as the Jedi and the Sith fought, their lightsabers clashing in a spectactular display that brought the neighborhood kids out to watch and go "Ooooh" and "Aaaaaah". Soon, the battle was over, with only one leaving the scene of the fight. The only remnants of the loser were his robe sprawled out onto the ground, his lightsaber resting nearby. The kids, with the excitement over, shrugged and went inside to play Super Mario Bros.

Or, at least, that's what I think would be the most interesting explanation as to why there was a lightsaber and a Jedi robe abandoned on our driveway.