How do I make sitcky bouncy buttons?

Can someone tell me how I can make sticky bouncy buttons?
I’ve seen the effect in a few places.

One of the places where I’ve seen it is:

http://www.seanjohn.com/sj6/

When you put the mouse over the button, it kinda bounces and sticks to the mouse cursor.

Does any of the above make sense!?
Thanks.

OM