This came up in the "Atheist" discussion, but even if you're not interested in that this is an awesome little game to play with. Slide down to the micro level or zoom out to the macro....It's mind boggling just to think about it
http://www.newgrounds.com/portal/view/589217
DISCLAIMER: Obviously, especially in the case of subatomic particles "size" loses its meaning as we usually understand it, and the yes, electrons don't orbit like that... It's just something to play with and get you thinking.