Haha thats awesome man. That fake coin drop thing was taught to me by Jay Sankey in one of his "Bending the Real" videos. Here it is: http://www.youtube.com/watch?v=z2l2XdyC0-o
Usually besides a coin, you can use an interesting object, just to get a conversation going.
Eg "Hi, i think you might of dropped this",
"nah thats not mine,"
"oh, it sure is pretty isnt it?" .........