A Japanese prank I once saw proved that pedestrians get out of the way when they hear a bicycle bell from behind. You could do the same when you run by carrying a bicycle bell but if you want something smaller and a lot more practical consider the RunBell. Made of brass to make a beautiful sound, the Runbell has a beautiful and refined look to it. It is slightly oversized to fit fat fingers but silicone insert are included to fit smaller ones. You can even use them with gloves on. It's simple yet brilliant.