Hey can anyone tell me the name of this effect and where I can find it?
http://www.youtube.com/watch?v=OxuNTwioXcM
There are actually several ways you can do this, some impromptu, some not impromptu.
For the non-impromptu, try looking into stacks, and from there, it should be pretty easy to come up with your own method.
For the impromptu version, look into a term called "clocking".
Also, you will need to be performing for the beautiful, Ms. J. Wang, for it to be successful! SHOUT OUT TO J. Wang!