Psychic Surgery

(01/06/2011)
You look at the top two cards of that library as the triggered ability resolves. That happens after your opponent is done shuffling.

(01/06/2011)
If your opponent’s library has one card in it and they are instructed to shuffle that library, Psychic Surgery will trigger. You may’ exile the one card in that library.

(01/06/2011)
In most cases, Green Sun’s Zenith instructs you to shuffle your library twice. Although shuffling that library only once is an acceptable shortcut, Psychic Surgery’s ability will still trigger twice.